Jake Gyllenhaal stars in David Ayer's 'End of Watch.' (Supplied) 'End of Watch' an eyeopener

There's a good reason why David Ayer has written so much about the police.

Tossed out of the house as a teenager, he lived with a cousin in Los Angeles and wound up on the mean streets of South Central, where the police are not regarded as anyone's buddy.

Ayer, 44, captured some of his youthful experiences in the film Training Day, which he wrote, and Harsh Times, which he wrote and directed. End of Watch, which he also wrote and directed, is the cop crime drama that brought him to TIFF and to Toronto earlier in September; the film stars Jake Gyllenhaal and Michael Pena as gung-ho police partners who stumble into the work of a major drug cartel and get into a crime scene way over their heads. It opens Friday.

Growing up in South Central, says Ayer, he saw a lot of the police, and not in a good way. But as End of Watch illustrates, "To the LAPD's credit, they've evolved. It's a totally different department now. They're good people. That story could never be accurately told."

The corruption and violence Ayer saw growing up is where Training Day came from. "Because I knew that side of the police, that other people didn't see. It was until Rampart broke," he says, referring to the late '90s corruption scandal in the anti-gang unit of the Los Angeles Police Department, "that people understood that the script Training Day was about real things. So many studio people told me, 'You don't know anything about the cops.' But these are people who call 911 when someone steps on their flowers.

"You could call 911 in my neighborhood growing up, but the police wouldn't come."

As for End of Watch, his riveting new police movie, Ayer explains he wanted viewers to be right in the middle of the action. "It is brutal," he concedes.

"When a movie is a cartoon, more stylized, there's a separation that happens, a psychological separation. I went to great pains to remove any protection the audience has to separate themselves from that world. So even the camera techniques mimic the style of cameras used in the real world to capture real things." A cop friend showed Ayer the footage from a video camera he took to work every day. "He showed me what I guess you'd call a highlights reel, of fights and car chases and gun fights and encounters with the public, and it was riveting. It was the first time I'd seen footage of cops filming themselves at work, as opposed to being filmed by others, and it just seemed like a fantastic tool to bring to a police movie." He emphasizes that End of Watch is not a 'found footage' film. "That's almost a pejorative these days.

"This is a hybrid," he says. "It's not really a found footage film, but I used that, and a broken editing style, and broken composition, and I destroy everything that tells us the movie should work. I literally burn the rule book and somehow it works.

"And the only reason it works is because of Mike and Jake, and the performances they're able to deliver."

liz.braun@sunmedia.ca