ARVADA, Colo. — The fatal shooting of an Arvada Police officer this month started with a custody dispute between the suspect and the mother of his children that led to a family fight in the street outside the suspect's apartment, according to the arrest affidavit in the case.
According to the affidavit, the suspect, Sonny Almanza, 31, said that he didn't know there were police officers present when he started shooting in the early hours of Sept. 11 on West 51st Avenue near the intersection with Marshall Street.
Almanza is charged in the murder of Arvada Police Officer Dillon Vakoff, 27, and is also accused of injuring a woman in the same incident.
On Monday Jefferson County District Court released the arrest affidavit for Almanza, which describes the Arvada Police Department's investigation into the events that happened on the night Vakoff was shot and killed.
In the early hours of Sept. 11, Almanza was in downtown Denver with his sister, Destiny Medlock, and his brother-in-law, Jacob Marrujo, according to the affidavit. Almanza consumed two shots of alcohol, according to the affidavit.
While he was out, Almanza heard that Lexis Lopez, the mother of his two children, who he broke up with two weeks before, wasn't with the children and had left them in the care of another family member, according to the affidavit.
Almanza, Medlock and Marrujo drove to Lopez's mother's house in Thornton. When they arrived, Almanza heard crying from outside the home and went in through an unlocked door, the affidavit says.
Almanza found the two children had been left in the care of juveniles related to Lexis Lopez. He took the children and started driving to his Arvada apartment with Medlock and Marrujo.
While on their way, Almanza said he got threatening texts and phone calls from Lexis Lopez, the affidavit says. Almanza told police that Lopez said other members of her family were on their way to Arvada and intended to start a fight to get the children back, according to the affidavit.
While the three were driving to Arvada with the children, Medlock called Jeffcom Dispatch to request officers respond to the apartment on West 51st Avenue, according to the affidavit.
As they were driving on West 51st Avenue, Almanza noticed several parked vehicles that belonged to Lopez's family and associates, the affidavit says.
About 1:45 a.m., Arvada Police Officers D. Garibay and Vakoff responded to an apartment building at 6753 W. 51st Ave. for a call of a disturbance over the custody of two children, according to the affidavit.
When the officers arrived on scene, Lexis Lopez told them that Almanza had taken their children from her mother's house and brought them to his apartment, police said in the affidavit.
As Lopez was talking to officers, another vehicle arrived in the parking lot, and a fight started shortly after, according to the affidavit.
Almanza told police he had reason to believe that Lopez's family carried firearms. He went into his apartment to get his rifle, the affidavit says.
Almanza fired the rifle one time into the air from a grassy area to the east of the apartment building, according to police. Lexis Lopez' sister, Mercedes heard the gunshot and started running toward Almanza, police said in the affidavit.
Almanza continued to walk toward the fighting and shot Mercedes in the leg as she approached him, the affidavit says.
As Almanza walked between two cars parked side by side, he was shot on the outside of his right hip. Almanza turned and saw someone was between two nearby parked cars, according to the affidavit.
Almanza pointed the rifle and shot at the person, not realizing until later that the person was a police officer and not a member of Lopez's family, according to the affidavit.
Almanza ran into the backyard and threw his rifle away, stating he did not want anyone else to get shot. He returned to the front of the apartment building and was taken into custody by another officer, the affidavit says.
During the investigation, police learned that Lexis Lopez and Almanza had no formal child custody agreement.
Almanza's criminal history shows he had previous charges for multiple weapons-related offenses and convicted of first-degree assault, according to police.
The on-scene investigation showed eight rounds hit the south wall of the apartment building, according to police. This wall was directly behind where Vakoff was located, according to the affidavit.
When Almanza shot Mercedes Lopez, she was near the vehicle where both children were located, police said. This was the same vehicle that Almanza arrived to the scene in and would have been aware of their presence in the vehicle, the affidavit says.
RELATED: 'I’m not sure how to continue on': Girlfriend of fallen Arvada officer recalls their time together
SUGGESTED VIDEOS: Latest from 9NEWS