They say that out of tragedy comes hope, and one woman was doing her best to instill that following the death of two police officers in Des Moines on Wednesday.

In a video taken by a local news station, an emotional moment was captured between the woman while she handed a box of bottled water to a cop in the street, reducing the man to tears.

'This is the only way I know how to help - to feed,' the woman says, before embracing the officer.

The Iowa city has been rocked by the murder of two officers were executed in separate ambushes by alleged gunman Scott Michael Greene, 46.

Emotional: Footage captured by a TV station in Des Moines shows a local woman handing a police officer a box of water following the execution of two officers early Wednesday

Teary: Both the woman and the officer are reduced to tears by the touching exchange

Touching: In a video taken by a local news station, an emotional moment was captured between the woman while she handed a box of bottled water to a cop in the street

In the touching footage, which was taken by KCCI, the woman first breaks down while trying to comfort the officer. She makes it sound as if her father and some of her friends are also police officers.

'I want you to go home to your families, because I want my dad to come home to me, and I want my friends to come home to me,' she says.

'I'm sorry, and I am here for you all. I don't know how else to help or what else to do.'

The officer, through tears, tells the woman: 'Your prayers are all we need.'

The two finish off their hug and the woman promises to continue praying, before she walks away.

This undated photo shows Urbandale resident Scott Michael Greene, 46

Authorities said two officers that were killed were ambushed while patrolling in their cars during the early morning hours Wednesday, in separate shootings two miles apart.

"It doesn't appear that either officer had an opportunity to interact with the suspect," Parizek said. "They didn't have a chance to defend themselves."

Urbandale Police Chief Ross McCarty said evidence at one of the shooting scenes suggested that between 15 to 30 shots were fired from a .223 caliber weapon, and that the gunman had likely walked up to the police cars on foot.

The two officers killed were identified as Anthony Beminio, 39, an 11-year veteran of the Des Moines Police Department, and Justin Martin, 24, who had served one year on the Urbandale police force.

Martin was found dead just after 1:00 am next to Urbandale High School, police said. Twenty minutes later, Beminio was discovered gunned down at a nearby intersection. US media said he died after being taken to the hospital.

Urbandale police officer Justin Martin, 24 (right), and Des Moines police Sgt Anthony Beminio, 39 (left), have been identified as the officers killed in the shootings

Greene turned himself in, authorities said, by flagging down an Iowa state parks employee while walking on an unpaved rural road. He was taken to a local hospital complaining of an unspecified ailment unrelated to his capture, and would be interviewed "once he's well enough to make a statement," Parizek said.

Authorities declined to comment on a motive for the shootings, saying they were still conducting an investigation.

Greene had a history of run-ins with Urbandale police officers and was well-known to law enforcement, McCarty said.

He had recently been removed by police from an Urbandale High School football game -- a school Greene's daughter attends -- after he waved a Confederate flag during the national anthem.