Three police agencies are investigating the Tuesday drive-by shooting at Granger High School and possible connections with an incident at Cyprus High in Magna the same day.

An 18-year-old man remained in jail Friday for investigation of aggravated assault in connection with the incident at Granger. Officers planned to execute a search warrant Friday afternoon for the weapon that may have been used, before reviewing possible charges with the Salt Lake County Attorney's office.No one was injured when a shot was fired from a car carrying seven or eight people that pulled into the Granger High parking lot Tuesday at about 2:50 p.m. The shooting followed an exchange of obscenities and hand gestures common to the rival Bloods and Crips gangs.

Salt Lake County juvenile detectives are investigating reports that a black male threatened a Cyprus High student with a handgun in a separate incident the same day. Which incident happened first, the one at Cyprus or the one at Granger, is still being determined.

West Valley police Det. Kurt Imig said it wasn't until after his department and Granite School Police officer Craig Ellersten had identified a suspect in the Granger shooting that possible connections with the Cyprus incident came to light.

"We're working with county detectives and the resource officer at Cyprus" to see if additional charges will be considered against the suspect already in custody. Officers did not say how many additional arrests may follow.

Booked into jail Wednesday for investigation of aggravated assault was Robert Lee Martin, who is being held without bail.