Context: Police officers Brian Taylor (Jake Gyllenhall) and Mike Zavala (Michael Pena) are close friends and partners in the Los Angeles Police Department. Taylor is filming their police activities for a film project, attaching small cameras to his and Zavala's uniforms and carrying around a camcorder, much to the dismay of their peers and superiors. After shooting two suspects following a high speed chase, the shooting is declared justified by the D.A. and the officers are commended for their actions. Taylor and Zavala's antics are met with scorn by fellow officer Van Hauser (David Harbour).The officers respond to a call regarding a man, Mr. Tre (Cle Shaheed Sloan) scaring off a mailman while intoxicated. Upon arrival, Tre hurls racist insults at the Hispanic Zavala, who responds by accepting a fight, to Taylor's approval. Zavala beats him soundly and arrests him, but wins the man's respect for both fighting fair and not mentioning the fight in the report (which may have sent Tre to prison for life due to Three Strikes). Later that night, Tre and his friends are shot at by a group of Latino gang members and one of his friends is killed. The officers find the now-burnt vehicle used in the drive-by the next day, but are shooed off the scene by homicide detectives as well as Van Hauser, who warns them they will get screwed over by the LAPD someday.Responding to a missing persons report, the officers discover two children bound and locked away in a closet and arrest the distressed mother and her drug-addict husband.The cops arrive as a group at a loud outdoor party, the Hispanics from the drive by shooting are celebrating. The cops and partiers verbally joust and Brian sizes up the gang leader, Big Evil (Maurice Compte). The cops depart telling them to keep the noise down.Taylor begins dating Janet (Anna Kendrick) and feels Janet is the only girl he's dated who can connect with him on an intellectual level. Zavala, who is married and expecting a child, offers him relationship advice.Investigating the South Central area, Taylor has a hunch and determines to scope out the home of the mother of a known gang member and sees an expensive pick up truck in the driveway. A woman walks out of the house and delivers a large soup saucepan with lid to the man in the truck. As the truck drives away, the officers follow and then pull over the man in the truck, ostensibly for having CD hanging off the mirror and illegally obstructing the front view, which is minor traffic violation in California per VC 26708 . As Zavala approaches the driver's window to make contact, the driver suddenly draws a gun and fires, and Zavala deflects the man's arm just in time to avoid being shot. After arresting the driver, the officers find an ornately-decorated, compact .45 Colt automatic pistol, a gold-plated AK-47 rifle, and a large amount of money in his truck (hidden in the soup pot). As revealed later, the money and firearms are connected to a Mexican drug cartel operation in the South Central area as well as the gang that did the drive-by on Tre and others.Days later, the two officers are first responders at a house fire that has trapped children on the second floor. Zavala and Taylor enter the house and rescue two young children and are nearly overcome by heat and smoke. When the mother informs them that a third child remains inside, Zavala to rushes to the aid of the remaining child as Taylor reluctantly follows, barely making it out alive. The two are commended and receive the Medal of Valor for their actions, but Taylor has mixed emotions about the situation. Using the house fire incident as leverage, Taylor convinces Zavala to further investigate the South Central incident, to Zavala's chagrin. Arriving at the house, Taylor and Zavala notice suspicious behavior from outside and enter. They arrest another man, who is also in possession of several ornate firearms: a .45 Colt automatic similar to the first one found at the traffic stop, and a Walther PPK. Investigating further, Taylor discovers a hidden stash of Mexican and Asian 
 Question: Who ambushed the officers?
Output: big evil and his gang