By Melissa Garcia

HIGHLANDS RANCH, Colo. (CBS4) – A Douglas County deputy was killed Sunday in what authorities said was an ambush-style shooting in which rounds struck seven people.

Deputies first arrived at the Copper Canyon Apartment Homes on County Line Road near University Boulevard around 3 a.m. after a resident complained of loud noise at a neighboring apartment home.

The second call to deputies came at 5:14 a.m., alerting them of a more serious “disturbance” at the apartment in question.

Law enforcement officers set up a perimeter, including a special weapons and tactical team, in case the disturbance moved away from the immediate area.

Ahmed Hairi, who works nearby, described the flood of police activity that he saw outside when he began his shift. “The sniper, the SWAT, a helicopter,” he said. “It’s so crazy. I’ve never seen (anything) like that.”

At 5:17 a.m., a responding deputy arrived at the apartment complex again. Deputies were able to enter the unit with the help of a male roommate, who believed the suspect may have been having a mental breakdown. Deputies began talking with the suspect, who had barricaded himself in a bedroom, explained Tony Spurlock, Sheriff of Douglas County.

“We respond to every call anticipating that everyone has a gun. This is Colorado,” Spurlock added.

Deputies, however, may not have anticipated the violent attack that happened next.

The suspect fired more than 100 rounds from a rifle, Spurlock said, killing one deputy and injuring four other law enforcement officers in an ambush style shooting.

Two apartment neighbors, also struck by the gunfire, were rushed to an area hospital and were expected to survive.

One witness recorded video on his cell phone of the rapid fire shots.

“It’s a little bit unnerving,” one neighbor told CBS4’s Melissa Garcia. He was one of hundreds affected by a code red alert that kept people out of the area and urged Highlands Ranch residents to hunker down away from windows to avoid the dangerous shooter. “We need to have mental health checks for those that possess firearms. That’s what it comes down to,” the neighbor said.

Authorities identified the deceased deputy as Zackari Parrish, 29, who had worked for the Douglas County Sheriff’s Office for seven months.

Parrish, who suffered multiple gunshot wounds, leaves behind a wife and two young children.

“It was very difficult today to go see Zack for the last time,” Spurlock said.

“When I sat with his wife and held her hand I could see in her eyes that her life was over,” Spurlock said. “His wife told me today that he loved this job. Loved it more than any other job he’d had.”

A GoFundMe page has been set up to help the family of Deputy Parrish. Officials with GoFundMe confirmed to CBS4 that they are working with the organizer, Tyler Scott, all the money will go to the family.

“It’s heart-wrenching,” one neighbor said. “Honestly, anybody who is a human being and passionate, you have to feel for these people.”

Authorities said that all law enforcement officers involved were wearing bullet-proof vests and body cameras.

The other deputies who were shot were identified as Mike Doyle, 28, Taylor Davis, 30, and Jeff Pelle, 32. Castle Rock Police Department Officer Tom O’Donnell, 41, was also shot.

The four surviving officers were all “stable,” said Spurlock.

Deputy Pelle is the son of Boulder County Sheriff Joe Pelle.

“Jeff underwent surgery as a result of his injuries, and is recovering,” the Boulder County Sheriff’s Office tweeted.

“We are currently with our son and his wife,” Sheriff Pelle and his wife, Stephanie, were quoted as stating. “He is in good spirits considering the gravity and severity of what occurred earlier this morning. Our hearts ache for all those involved, and we are not only praying for Jeff’s recovery, but for the recovery of everyone involved, and for the family of the fallen deputy.”

Sheriff Pelle (Boulder SO), Deputy Pelle (Douglas SO), and family, earlier this afternoon. #CopperCanyonOIS pic.twitter.com/24ltoj6YpP — BoulderCountySheriff (@BldrCOSheriff) December 31, 2017

The the deceased shooter has been identified as Matthew Riehl, 37.

Douglas County Coroner confirms shooting suspect in #CopperCanyonOIS as Matthew Riehl DOB 9/09/80 (pictured). Investigation still ongoing and being investigated by @DA18th Critical Response Team. pic.twitter.com/H6wT0klSQv — DC Sheriff (@dcsheriff) January 1, 2018

Spurlock said the investigation at the scene would continue for two to three days.

To donate to the Douglas County Sheriff’s Office Fallen Officer Fund, click here.

We have ordered flags to be lowered until sunset Tuesday, Jan. 02, 2018, in honor of Douglas County Sheriff’s Deputy Zackari Parrish. Our hearts are with the Parrish family and his loved ones, and those affected by this tragedy. https://t.co/Irbl88JSBB pic.twitter.com/y5CMPnKV94 — John W. Hickenlooper (@GovofCO) January 1, 2018

Melissa Garcia has been reporting for CBS4 News since March 2014. Find her bio here, follow her on Twitter @MelissaGarciaTV, or send your story idea to mkgarcia@cbs.com.