Further doubt was cast on the police investigation into the murder of Katzrin schoolgirl Ta'ir Rada after it was revealed Monday that key DNA tests in the case were found to be inconclusive. Earlier, Rada's mother said she did not believe that jailed suspect Roman Zadarov was the murderer. According to a Channel 2 report, following a meeting of top Northern District police officers to discuss the results, they decided to send the DNA samples to a laboratory in the United States for additional tests. Channel 2 also revealed that earlier reports in which Zadarov claimed that Rada had asked him for a cigarette were simply untrue. Instead, police said, it was other students at the school who told police that the fatal confrontation between Zadarov and Rada began over a cigarette. Nevertheless, Northern District Police chief, Cmdr. Dan Ronen, said Monday that he was convinced that Roman Zadarov was indeed the murderer. Last week, police extracted a confession from Zadarov, who admitted to murdering the eighth-grader in a bathroom at the Nofei Golan high school and even reenacted the crime. But less than a day later, Zadarov recanted. Since then, the 29-year-old Russian immigrant has claimed that police pressured him in to a false confession. Zadarov's pleas of innocence found support from an unusual source earlier Monday, as the victim's mother, Ilana, said in an interview that she believed that high school students and not the construction worker, were behind Ta'ir's brutal murder. "When police told us that they had found the murderer and still refused to give us answers to the questions we asked, a red light turned on in my head," said Ilana who has repeatedly requested that police cooperate with a private eye hired by the family. In an interview with Israel Radio, Rada said she believed that other teens - not necessarily Nofei Golan students - had killed Ta'ir out of jealousy. "There was a lot to envy about her," Rada said. "Even though she wasn't a snob." Ilana Rada also implied that she believed the students were members of a Satanic cult, adding that the police should investigate that angle. "In my investigations I found that there was a Satanic cult inside the school and I was shocked," she added. "Students told me that they had a female ringleader who terrorizes the school." On Monday police continued to search the school's bomb shelter where Zadarov was working immediately prior to Rada's murder, hoping to find the knife with which Rada was killed hidden.