Despite the lack of a murder weapon and a clear motive, Nazareth District prosecutors on Thursday formally charged Katzrin resident Roman Zadorov, 30, with the murder of Ta'ir Rada, the 13-year-old girl found knifed to death inside her high school's bathroom 44 days ago. According to the indictment filed in Nazareth District Court, police say Zadarov - a Russian immigrant and father with no previous record - cornered Rada in a bathroom stall at her Nofei Hagolan High School when he was doing repairs on the campus. Police say Zadarov slit the eighth grader's throat and cut other parts of her body with a utility knife, before stepping on the body as he fled the scene. On Thursday, Galilee chief investigator Nir Mariesh said police "had no doubt" Zadarov was responsible for the murder, despite the fact that police have yet to find the murder weapon or establish a motive for the killing. Mariesh said a motive was not always required to prove a murder. "This is not Agatha Christie," he said, citing a similar situation in which a serial killer from Haifa was convicted of four murders without police ever establishing a motive. Mariesh also dismissed public criticism that police had neglected other potential suspects in their rush to indict Zadarov. "Every piece of evidence has been checked and every lead has been followed up, regardless of whether it was provided by public or private investigators," Mariesh said. "Each person who was in the area was checked thoroughly and we are convinced the correct man is being tried for murder." Arrested in the days following the murder, Zadarov admitted to killing the eighth-grader and even cooperated in a recreation of the crime, only to recant after initial blood samples proved inconclusive. The Rada family hired a private investigator after police requested a total of six remands and seemed to struggle to find conclusive proof against Zadarov. The private investigator reportedly cited eyewitness accounts in suggesting students or teenagers from outside the school may have been involved in the killing. The Rada family had suggested police check whether a rumor that a satanic cult consisting of students at the high school may have killed Ta'ir out of jealousy. After saying a month ago that she believed police had the wrong man in custody, at Thursday's hearing Ilana Rada said that now it did seem that Zadarov was involved with the murder of her daughter. However, she said she was convinced that he did not act alone, but that the family wouldn't "undermine the police work" at this stage. "I have trouble believing that the case is solved," she added. Roman Zadarov repeatedly denied any connection to the murder during Thursday's court proceedings. "I don't have the blood of Ta'ir Rada or any other person on my hands," the prisoner said. Ch.-Supt. Shmuel Bokler, lead investigator in the case, said forensic evidence and Zadarov's initial confession provided the key evidence in the decision to indict. A footprint on the teen's pants matched those of shoes worn by Zadarov on the day of the murder, police said, and a hair sample found on the scene and sent for testing in an American forensics laboratory was shown to be a 90% match to Zadarov's. According to the indictment, at 1:30 in the afternoon on December 13, Ta'ir Rada was sitting with friends in the school's courtyard following a drama lesson, when she entered the school to get a drink of water. Police say Zadarov, who was renovating a bomb shelter on the premises at the time, spotted Rada and followed her into a second floor bathroom with the intent to murder her. Zadarov confronted and then attacked the teenager, who attempted to take refuge in a toilet stall. At this point Zadarov pulled out a knife and forced open the door, slashing Rada across the neck, face and chest. Defensive wounds were found on the girl's arms, indicating that she struggled to fight back before she collapsed and died from massive bleeding. Police say Zadarov locked the bathroom from the inside, and then climbed out of a window above the stall, stepping on Rada's legs in the process. Once outside, he switched the blade on his knife and rinsed off signs of the bloody struggle. Zadarov returned to his work in the bomb shelter at 5:30, police said, after he had changed and hid his shirt and pants, along with the knife blade used in the murder. Police said they expected the initial proceedings of the murder trial to begin as early as next week.