A 12-year-old girl died from injuries related to a crash with a BMW sedan on the night of April 15, Thornton police announced Thursday.

The announcement comes nine days after the crash, which also resulted in a 38-year-old man dying in the hospital. He and the girl were riding a motorcycle together when when they were struck by the BMW.

At about 8:15 p.m. on April 15, a 17-year-old male driving the sedan was turning southbound onto Welby Road when he crashed into a Harley Davidson motorcycle, with two people riding it, traveling eastbound on Thornton Parkway, Thornton police said in a news release on April 16.

Both people riding the motorcycle — the 38-year-old man and 12-year-old girl — were transported to the hospital. The male died at the hospital and the girl was in critical condition until she died nine days later, police said. The driver of the BMW was arrested on suspicion of careless driving causing death and released pending further investigation.

Anyone who witnessed the crash or has information that has not yet been shared with investigators is asked to call the Thornton Police Department tip line at 720-977-5069.