( CNN ) -- A 26-year-old man was arraigned Tuesday on murder charges in the January strangling deaths of his girlfriend and her four small children in an Oklahoma apartment . Joshua Durcho told a friend he choked Summer Rust but said her children were elsewhere , an affidavit says . Joshua Steven Durcho is charged with five counts of first degree murder in the January deaths of Summer Rust , 25 ; her son Teagin , 4 ; and daughters Evynn , 3 , and Autumn and Kirsten , both 7 . All five bodies were found January 12 in Rust 's apartment in El Reno , Oklahoma , about 30 miles west of Oklahoma City . Authorities believe Durcho killed Rust because she threatened to call the police on him , prosecutors said in court documents released Tuesday . He knew that likely would bring about his arrest , the documents said , because two outstanding bench warrants had been issued on him after he failed to appear in court in two criminal cases -- one on charges of driving under the influence and the second on charges of unlawful possession of a controlled dangerous substance . Durcho had previously served time in prison after being convicted of unlawful possession of marijuana and `` vowed he would never go back to prison , '' the court documents said . Prosecutors intend to seek the death penalty against Durcho , according to the documents , which note each victim suffered `` severe pain and anguish '' as they fought for their lives while being strangled with a ligature , which could include a string , cord or wire . In addition , the documents said , evidence indicates Durcho sexually abused both the 7-year-old girls at or near the time they died . In Tuesday 's arraignment , Canadian County District Judge Edward Cunningham entered not guilty pleas on Durcho 's behalf , according to The Oklahoman newspaper . An affidavit filed in the case , written by an Oklahoma State Bureau of Investigation agent , said Durcho went to the home of an acquaintance January 12 and said he had `` choked '' Summer Rust -- identified in court papers as Summer Garas -- to death and was leaving Oklahoma . When the acquaintance , a women , asked Durcho about Rust 's children , he `` told her that the children were at their grandmother 's residence ... while he and Summer worked out their relationship problems , '' according to the affidavit . The acquaintance then called Durcho 's mother , who drove to the apartment but received no answer at the door , the affidavit said . She asked her nephew , Durcho 's cousin , to accompany her , leading to the discovery of Rust 's body . The cousin notified police , and responding officers found the children 's bodies in the apartment . According to the court documents released Tuesday , Durcho also told the female acquaintance that he killed Rust because she threatened to call the police on him . Durcho was arrested in Hamilton County , Texas , the day after the bodies were found . He has been appointed public defenders , according to Canadian County , Oklahoma , court records , and earlier waived his right to a preliminary hearing in the case . CNN 's Ashley Broughton contributed to this report .
NEW : Court papers say woman , Two kids suffered `` severe pain and anguish '' NEW : four 7-year-old girls sexually assaulted before they died , documents say . NEW : Threat of returning to prison motivated slayings , prosecutors say . Bodies found Tuesday in apartment in Oklahoma , El Reno .