On Thursday night, an upstate man allegedly abducted and raped a 10-year-old girl and killed her mother. David Renz, 29, was somehow able to cut off his ankle monitoring bracelet—which he had due to federal child pornography charges—without authorities knowing before he allegedly committed the rape and murder. Renz appeared in federal court late Friday with a swollen face and a broken nose after a fight in a holding cell. Renz told investigators he didn’t want to press charges against anyone over the fighting.

It's unclear why Renz was put into a holding area with other prisoners, which is not the usual practice in holding someone facing such accusations. Renz has now been segregated from other prisoners and is being watched around the clock. "We're dealing with a man who is innocent until proven guilty," said Sheriff Kevin Walsh. "He's got to be protected."

Police are still investigating how Renz deactivated his ankle bracelet around 7 p.m. on Thursday. Renz graduated cum laude from State University College at Oswego in 2011 with a bachelor’s degree in computer science; when he was arrested on child porn charges last year, police needed Renz to supply the key to encrypted material on his computer.

Renz has been accused of carjacking 47-year-old elementary school librarian Lori Bresnahan as she was leaving a gymnastics class at a mall in the Syracuse suburb of Clay with her 10-year-old daughter around 8:30 p.m. on Thursday night. Renz allegedly tied up Bresnahan while he raped the young girl in a deserted part of the mall parking lot. The child was able to escape after Renz began fatally stabbing Bresnahan. The young girl was found by a passing motorist, who called 911 and informed them of Renz's location.

Renz admitted last year to using the Internet for the past six years to download about 100 gigabytes of child porn, made up of more than 500 videos and more than 3,000 images. He was charged in January with possessing child pornography, but was allowed to remain free under terms that included staying off the Internet and away from places including schools, parks and arcades. However, he lost his job at at the Wegmans supermarket after the arrest.

Despite the fact that Bresnahan and Renz were both at SUNY Oswego between 2009 and 2011—she was an adjunct professor and he was a student—police say they have “every reason to believe that this was a random act.”

Here's how the Syracuse Post-Standard described him in court:

As he appeared in federal court in leg-irons and handcuffs, Renz stood no more than 5 feet tall with a slight build, weighing not much more than 100 pounds. His straight black hair was mussed. He has a pronounced, misshapen chin.

The 10-year-old who was attacked is recovering with family now. “As with all tragedies the family will gain strength from each other and help the little girl live her life surrounded by love,” said Bill Senke, Bresnahan’s cousin.