A 21-year-old St. Petersburg man is dead. Now 3 teens face murder charges.

Three teenagers are facing murder charges after St. Petersburg police found a 21-year-old man dead in the 100 block of 80th Avenue NE on Saturday.

At about 1:15 p.m., St. Petersburg police found Marcus Rivers, 21, in his car. He was dead from a gunshot wound, police said in a news release.

Officers also found 17-year-old Tyvion Royal at the scene. He also suffered a gunshot wound. Royal was one of three people who confronted Rivers in an attempted robbery, police said. Investigators were awaiting ballistics report to help determine how Royal was injured.

Royal was taken to Orlando Health Bayfront St. Petersburg, where he was in critical but stable condition on Sunday. He faces charges of first-degree felony murder and armed robbery, as well as a gun charge.

Samarion Douglas, 16, a second suspect in the shooting, also faces first-degree felony murder and armed robbery charges, police said.

Police on Monday announced the arrest of the third suspect, 16-year-old Randy Reynolds, on charges of first-degree felony murder and armed robbery.

Police said investigators believe the attempted robbery was drug related and that the people involved knew one another.