A government attorney for the Philippines was fatally shot in an Uber while visiting Philadelphia, officials said Sunday.

John Albert Laylo was heading to Philadelphia International Airport with his mother to board a flight and was stopped in the Uber at a red light near the University of Pennsylvania around 4:10 a.m. Saturday, officials said.

Several rounds were fired into the Uber from a black car behind it, police said. The black car then pulled up alongside the Uber and fired several more rounds into it, police said in a news release.

Laylo was shot in the back of the head and taken to a hospital, where he was pronounced dead Sunday, police said.

No one was arrested, and no weapon has been found, police said. Authorities did not offer a suspected motive or say whether Laylo, his mother or the Uber driver were intentionally targeted. Homicide detectives are investigating and are looking for surveillance video.

The consulate general of the Philippines said the victim was an attorney for its government, Philadelphia’s KYW-TV reported.

It wasn’t clear whether the Uber driver or Laylo’s mother were injured, but the latter posted to Facebook on Sunday, indicating she had been hit by shrapnel and saying she had been on vacation with her son, whom she referred to as Jal and said was 35 years old.

“Never did I imagine or dream that … the end of our vacation will be like this!” Leah Bustamante Laylo wrote in a post accompanied by snapshots of her and her son touring sites in New York, Washington and Philadelphia. “We travelled together and we are supposed to go home together! I will bring him home soon in a box!”

Philadelphia, along with other large U.S. cities, is experiencing a surge in gun violence. In one notable episode June 4, a gun melee in the South Street entertainment district, about 3 miles from the shooting that killed Laylo, left three people dead and several others injured.