Double police killing suspect Scott Michael Greene 'filmed holding Confederate flag'

The man suspected of killing two police officers in an 'ambush-style' hit in Iowa appeared in an online video holding a Confederate flag, and in another arguing with a police officer.

Scott Michael Greene, 46, was arrested after two police officers were shot dead in a suburb of Des Moines in the early hours of Wednesday. The officers were found dead in locations three miles apart in Urbanville.

Authorities said Greene surrendered to a Department of Natural Resources officer in Dallas County at 9.30am local time. He was taken to a hospital in Des Moines. Police did not reveal details of his condition.

Footage has emerged of Greene holding the divisive Confederate flag as well as the Stars and Stripes at a local American football match in front of black spectators.

The flag is associated with support of the slave-owning Confederate states during the American Civil War, and has become an increasingly controversial after pictures emerged of white supremacist mass killer Dylann Roof holding it.

Critics argue the flag is a racist symbol and several state legislatures have banned it, however others claim it is a symbol of southern identity.

In another video posted to the same account Greene challenges officers apparently asking him to leave school property.

"Have I committed a crime?" Greene asks police, who tell him he is "causing a disturbance in the stands" and could be arrested.

In the video entitled Police Abuse, Civil Rights Violation at Urbandale High School, he accuses the officers of assaulting him. "You grabbed me and shoved me around," he said.

The high school stadium is reportedly at the intersection where one of the officers was found dead.

Police said they are investigating the videos.

"Most police officers in the area are familiar with Greene," Urbandale Police Chief Ross McCarty said at the press conference. "They've taken trips to his home or delivered service to him, but nothing to this extent." McCarty said that Greene was issued a a trespass warning. Police were called when a woman complained Greene was waving the Confederate flag in front of some black people, reported Buzzfeed.

The Des Moines Register reports that man with Greene's details had several run-ins with police.

In April 2014, police attempted to search Greene for weapons at an Urbandale residence and he became "non-compliant, hostile, combative and made furtive movements toward his pockets", according to court records.

Two days later he allegedly threatened to kill a man in the parking lot of the same apartment and was charged with first-degree harassment. According to official records he abused a man using racial expletives and threatened to kill him.

He pleaded guilty to a lesser harassment charge, and was sentenced to a year on probation.