MEDELLÍN, Colombia — The local detectives pointed to the spot in the grass near a creek where the body was found. Eh Xiong walked toward it, listening to the water flowing, thinking about the final moments before his brother’s death.

Xiong, 56, had traveled from his home in Minnesota to Medellín in late December to try to understand what had happened to his brother, a 50-year-old U.S. citizen and well-known Hmong comedian and activist. Tou Ger Xiong was held for ransom, stabbed and beaten, and then thrown off a cliff. His corpse was found on Dec. 11 in one of the most dangerous areas of Medellín.

The grieving brother had come to this creek to perform a traditional Hmong ritual to liberate a deceased person’s spirit. He burned incense and gold paper as he said a prayer.

“I venture here today to this tranquil spot … where you took your last breaths of fresh air,” he whispered. “Regrettably, I stand here now, realizing I wasn’t by your side sooner.”

Last week, police arrested and charged four people in the kidnapping and killing of Tou Ger. His was one of at least eight “suspicious deaths” of U.S. citizens in November and December in Medellín, a popular destination for tourists visiting Colombia. The U.S. Embassy in Bogotá said the incidents seemed unrelated, but several involved similar circumstances.

“Criminals use dating apps to lure victims to meet in public places such as hotels, restaurants, and bars, and then later assault and rob them,” the embassy warned in a statement. “Numerous U.S. citizens in Colombia have been drugged, robbed, and even killed by their Colombian dates.”

“Let’s be clear: Medellín is a safe city,” said William Vivas, a public human rights defender in Medellín. “But as the number of tourists goes up, so does the number of certain phenomena around tourism.”

Tourism here has grown steadily since the 2016 signing of peace accords with the Revolutionary Armed Forces of Colombia, also know as the FARC. The country began promoting areas that were previously too dangerous to visit, and foreigners quickly poured into the country. The government has also offered new “digital nomad” visas to encourage Americans and other foreigners to live in the country.

The revival of Colombia’s kidnapping industry

Colombia was once infamous for its kidnapping industry. The FARC, then the country’s largest leftist rebel group, used the tactic to earn revenue and gain political advantages. Between 1996 and 2006, 23,144 people were kidnapped by the FARC and other criminal organizations, according to Colombia’s national police, an average of 5.7 people per day.

But public outcry, together with the creation of specialized anti-kidnapping entities, helped reduce kidnappings by 92 percent by 2013, according to the country’s then-police chief. As the FARC fighters laid down their weapons and signed the peace agreement, many Colombians hoped that kidnappings would remain a part of the past.

Now, though, as other armed groups have gained more control in places where the FARC withdrew, kidnappings have risen again. Last year, the number of people kidnapped soared to 287, police figures show, a figure the country hadn’t seen since 2014.

One of the most high-profile kidnappings was of the father of Liverpool soccer player Luis Díaz, who was held hostage for more than a week by the ELN guerrilla group.

Elizabeth Dickinson, a senior analyst with International Crisis Group, said armed criminal groups in Colombia are extorting protection “taxes” from families and businesses as a way to diversify their moneymaking portfolios and instill fear in the community. Sometimes these groups kidnap relatives and hold them hostage until the extortion is paid.

Last month, in a bid to advance peace talks with the government of President Gustavo Petro, the ELN announced it would no longer hold people for ransom — as long as the government funds projects that offer alternative sources of income.

Even in urban settings, kidnappings are not happening randomly, Dickinson said. Often, they are part of an organized network of control, as urban criminal groups aim to recruit more members and generate more income.

“These sorts of events disproportionately affect the perception of security that citizens have because it’s a practice that Colombia had thought it had moved beyond,” Dickinson said, “but clearly it’s come back.”

The case of Tou Ger Xiong

Tou Ger Xiong came to Colombia as a tourist at the end of November and rented an apartment in El Poblado, one of the most popular neighborhoods for foreigners in Medellín.

Back in the Twin Cities area, host to the largest Hmong population in the United States, he was a celebrity, a performer who used comedy, storytelling and rap to confront stereotypes and forge connections. He told audiences about how his father fought with U.S.-backed forces during the Vietnam War, how his family had to flee Laos because of that association and how he learned to navigate American culture while holding on to his heritage.

An enthusiastic traveler, Tou Ger had visited Colombia a half dozen times. On this trip, he told his brother, he planned to study trade and the stock market in the mornings and spend afternoons with friends. He was also learning Spanish.

On Dec. 10, at 7:15 p.m., Eh had just boarded a plane in Seattle when he saw his younger brother’s name appear on the screen of his cellphone. “Can you send me a couple thousand dollars?” Tou Ger asked. “I’m in a bit of a situation, but everything’s okay.”

This was not the first time he had asked his brother to wire money, so the request didn’t strike Eh as odd. Tou Ger asked for the money through PayPal, but Eh didn’t use the platform, so Tou Ger gave him a bank account number instead. The plane took off while the transaction was pending.

On the morning of Dec. 11, Tou Ger’s roommate saw his empty bed and filed a missing-person report. Then, an anonymous call alerted police to a body by the creek.

The prosecutor’s office reconstructed that he had been tied up and tortured in an apartment before being taken to a wooded area and thrown off the cliff. He had stab wounds on his chest and face, and his cranium had been crushed with a rock.

One of the four arrested in the killing was 19-year-old Sharit Gisela Mejía. It turned out Tou Ger had made another call that evening to ask for money. In that exchange, with a friend in Minnesota, he said he was being held against his will. His friend sent $3,140 by PayPal. And investigators traced the recipient account to Mejía.

Investigators say they believe Tou Ger and Mejía may have met each other online. They had gone to a Karol G concert at the beginning of December — they can be seen together in a video. And they were together on Dec. 10, too, according to the prosecutor’s office.

Prosecutors say they believe Mejía had been dating Tou Ger with the goal of stealing money. But when her boyfriend found out, he became jealous, prosecutors allege.

The boyfriend, a 17-year-old being held as a minor, pleaded guilty to the kidnapping and murder charges. Mejía pleaded not guilty, as did two other men: a 34-year-old law student and a 24-year-old who belongs to a criminal group that runs a drug business in the neighborhood, authorities said. The men had both previously been convicted of drug trafficking.

Tou Ger didn’t mention a potential date to his roommate before leaving the apartment.

“He just said, ‘Maybe I won’t come home tonight,’ ” said his roommate, who spoke on the condition of anonymity because of security concerns. “He was too good and trusted everybody. I told him to be cautious in Colombia.”

Weeks later, Eh traveled to Colombia and met with the prosecutor in charge of the investigation. He made arrangements to send his brother’s body back to Minnesota, and he carried out the ritual to bid farewell to his brother’s spirit.

According to Hmong custom, the ceremony must take place in the exact location where a person died. Standing at a distance were the police officers, a small entourage from Minnesota and Tou Ger’s roommate — the last of his acquaintances to see him alive.

Once the brief ceremony was over, a friend stepped forward with a bag with cigars, a bottle of whisky, a candle and purple flowers for the late Vikings fan.

“When we hung out, Tou Ger would pop up a cigar, have some whisky and say, ‘Just do one with me,’ ” Eh said.

So at the creek that day, Eh lit a cigar, poured himself a glass of whisky and splashed some on the ground for his brother.

Samantha Schmidt in Minneapolis contributed to this report.