SAN ANTONIO -

A 17-year-old was fatally shot in the chest Wednesday after an altercation with a 21-year-old man.

The shooting happened around 3:30 p.m. in the 9800 block of Alexa Place.

A 19-year-old boy was also shot. He was taken to the Christus Santa Rosa Hospital-Westover Hills with what police described as “very serious injuries” to his head.

According to police, the two teenagers got into an argument with the man.

Witnesses said they heard four to five gunshots just a few minutes after the argument.

Two witnesses tried to resuscitate the 17-year-old boy while they waited for paramedics to arrive.

A witness, who did not want to be identified, said the 21-year-old man approached the victim’s mother claiming he shot the boy in self-defense.

“He saw that the mother was there crying and yelling and he came over there trying to say, ‘I didn’t do it on purpose. They pulled out the gun and a knife and I shot,'” the witness said.

The 21-year-old man was taken into custody at the scene.

Police said they’ve responded to calls in the area in the past involving the same 17-year-old boy and 21-year-old man.