Girl arrested in park murder

Police have arrested a 15-year-old girl in the stabbing death of a teen boy Tuesday afternoon at a Montrose-area park. The victim, Gabriel Granillo, and two friends were attacked by 20 or 30 people at Ervan Chew Park in what police say was a gang attack; even though HPD said it believes the incident was an isolated incident, they're stepping up patrols in the area just in case.

Meanwhile, more details are merging about the attack: Tuesday, police said they believed Granillo was in a gang, but Wednesday they said he was "affiliated" with one — reportedly MS-13, which began among Central American immigrants in L.A. and has spread through Latin America and the U.S. Police said the assault seemed premeditated, and it might not have been an ambush: A witness saw Granillo arrive at the park armed with a baseball bat, and he was quickly joined by friends.

The witness, who did not want to be identified, said the two groups chased each other across the park several times before running into a nearby neighborhood, where they smashed car windows and slashed tires. The scene lasted "an intense 10 minutes," the witness said. "It just kept going back and forth," the witness recalled. "It was like they were fighting over the park."

Granillo stumbled through the park after he was stabbed, the witness said, and finally collapsed near a sidewalk. The suspect is a white blonde female, about 5 feet, 5 inches tall and 120 pounds, wearing a navy shirt and jeans, police said. HPD Capt. Dwayne Ready said police believe there were a couple of Hispanic females with the group, too.