Waltham man held without bail for allegedly stabbing a woman in a rooming house

A Waltham man was arraigned Monday on charges that he murdered a woman at a boarding house in Waltham early Saturday, a crime he confessed to, but said he committed in self defense.

A judge in Waltham District Court ordered Derrick Lopez, 18, held without bail.

At 2:40 am Saturday, police responded to a boarding house on Adams Street where they found the victim, Christin Tobin, 36, dead from several stab wounds, one to her left eye.


They also found Lopez, who told police that he had stabbed Tobin repeatedly, but only after she held him in a room against his will for more than two hours.

Get Fast Forward in your inbox:
Forget yesterday's news. Get what you need today in this early-morning email.
Thank you for signing up! Sign up for more newsletters here

Lopez told police he’d been walking in the area of Adams Street with his cousin, who wasn’t identified in the report, when he had to use the bathroom, according to police. He saw Tobin, on the porch of 20 Adams Street and asked to use her bathroom. According to the police report, Tobin agreed and allowed Lopez inside the rooming house.

Lopez told police that “immediately upon exiting the bathroom; the female grabbed a hold of him and forced him into a room.” She took his cellphone, Lopez said, and at one point threatened him with a pocket knife.

At some point, Lopez told police that he demanded Tobin return his cell phone and an argument ensued. Lopez said Tobin tried to attack him with the knife, which he eventually grabbed and began stabbing her.

“He stated that he felt like he was in a dream,” as it happened, according to the report.


The medical examiner ruled the cause of death to be sharp force trauma to the head, neck, and upper torso.

Lopez is due back in court for a pre-trial hearing on Aug. 29.

Family members outside Waltham District Court said he suffers from intellectual disabilities.

His cousin Yesner Espinal, 23, said Lopez had recently started a job at BJ’s Wholesale Club.

“He’s a good person,” Espinal said. “He never goes out. He stays home all the time and plays video games.”

Cristela Guerra can be reached at Follow her on Twitter @CristelaGuerra.