Los Angeles police officers fire tear gas into a Van Nuys apartment unit as they search for a reported second gunman after an LAPD helicopter was fired upon, forcing it to make an emergency landing. No second gunman was found. (Ringo H.W. Chiu, for The Los Angeles Times / April 24, 2011)

An 18-year-old man was booked on suspicion of attempted murder Sunday after he allegedly shot at a police helicopter in Van Nuys, rupturing its fuel tank and forcing it to make an emergency landing. A tipster's report of a second gunman set off an hours-long search and evacuations, but no suspect was found.

The Los Angeles Police Department helicopter was fired on after the pilot responded to a report of gunshots in the 15700 block of Saticoy Street about 6 a.m., Det. Gus Villanueva said. Officers who arrived in patrol cars saw San Fernando Valley resident Danny Lopez shooting at the copter from a yard, Villanueva said. Family members eventually tackled Lopez and held him until his arrest. A semi-automatic rifle was recovered, Villanueva said.

The helicopter, which was leaking fuel, landed at Van Nuys Airport and the pilot was uninjured.

"This situation could have easily turned tragic, and we were just fortunate," Assistant Chief Earl Paysinger said. "It's ironic that it happened on Easter Sunday. Someone divine was watching over us."

Officers offered no possible motive for the shooting. Villanueva said Lopez "was upset about a friend or family member who passed away."

Lopez was jailed at the LAPD's Van Nuys station.

As officers prepared to leave the area, they received a tip of another gunman hiding on the same block. A SWAT team determined the suspect could be in an apartment building. Tenants, many of whom were awaken by the gunfire, were evacuated. Some watched as dozens of officers swarmed the neighborhood. Other residents waited out the drama at a nearby elementary school auditorium, frustrated that their Easter plans had been derailed.

"We're waiting to see if we can go back to get [my grandson's] Easter basket and clothes," said Irene Garcia, 43, who stared hopefully down the street.

Authorities narrowed the suspect's possible location to two adjoining apartments. After calling into the apartments and receiving no response, they fired tear gas about 12:25 p.m., Villanueva said. A search failed to turn up a gunman.

Villanueva said an investigation will continue, although it was possible the tipster had been wrong. Residents were allowed back into their homes about 2:45 p.m. Several of them said that although the area is generally peaceful, gunshots have been heard occasionally over the last three weeks.

Elizabeth Bell, 46, who was watching television early Sunday when she first heard the gunfire, said she was shocked to learn that the target was a helicopter.

"On Easter too!" she said. "That's the day you're supposed to relax and chill and behave."