An anonymous tip helped detectives identify an 18-year-old as a suspect in an alleged assault that caused “significant injuries” to another teenager in downtown Colorado Springs on March 15, according to city police.

Detectives obtained an arrest warrant Thursday for Elijah Benjamin Valdez of Pueblo, who already was in custody at the Pueblo County jail on attempted homicide charges, according to court records.

In El Paso County, he faces charges of second-degree assault, possession of a weapon by a previous offender, menacing and violating a protection order.

The alleged assault occurred about 2:35 a.m.…