TOKYO — Japanese prosecutors dropped cases Friday against three of the four American teens suspected of attempted murder, according to U.S. and Japanese officials.

The fourth case was referred to family court, which in Japan handles cases involving people 19 and younger. The family court judge has as long as eight weeks to decide whether to treat the suspect as a minor or refer the case back to the adult criminal justice system. No charges have been filed.

Also on Friday, Japanese officials released all four teens — a 15-year-old, two 17-year-olds and an 18-year-old — to their parents, according to Air Force spokesman Maj. Christopher Watt. He said the families and military officials are continuing to cooperate in the case.

It was unclear Friday which teen still faced a possible charge.

Prosecutors declined Friday afternoon to elaborate on the recommendations it made to the court and they refused to identify which cases were dropped, saying they do not want to identify the teens because they are minors.

The four teens were arrested Dec. 5, suspected of stringing a rope across a street near the air base in August and causing a Japanese motorcyclist to crash. The woman, 23, who was driving suffered a skull fracture and lay in a coma for weeks. More recently, she has been able to return to work part time.

“Our thoughts are still with her,” Watt said Friday night in a telephone interview.

While awaiting prosecutor recommendations, the teens had been held separately at a local police station and then at four separate juvenile detention centers, according to military officials.

Last week, the teens’ parents — who are airmen at Yokota — visited with the victim’s family and offered apologies, Air Force officials said.