The Harris County Precinct 4 Constable's Office said the girl was receiving medical attention at the scene after she was hit by a car while riding a bike.
Police said the man was riding a bicycle on Quitman Street when he was hit by a driver who did not stop to render aid.
Deputies said the man was hit first by a driver who stopped, but when his girlfriend rushed to help him, another car hit her and took off. The two cyclists both died from their injuries.
Sheriff's office deputies are looking for an 18-wheeler driver who was allegedly involved in a hit-and-run Wednesday afternoon.
Loved ones have identified the 12-year-old as Zachariah Benjamin, who family members say was out playing at a friend's house before he was hit and killed by a driver.
A boy on a bike is dead after being hit by a car in a crash in northeast Harris County on Tuesday night, deputies said.