Tylor Crippen was stabbed to death on Jan. 29 while walking with his girlfriend. A tree was planted Saturday in the park where he was stabbed, in memorial of Tylor.

He was walking with his girlfriend that day when they were attacked by three teenagers. Crippen's girlfriend was able to get away.

Police arrested the three attackers, who are suspected gang members.

Following Crippen's death, neighbors began patrolling the south Modesto park on their bicycles.