A Pennsylvania mother charged with killing her 11-year-old son did it so the boy didn’t have to grow up under the stress of “the family’s financial difficulties.”

Ruth DiRienzo-Whitehead, 50, strangled her son Matthew as he slept with her husband’s belt, then locked the bedroom door and drove to Cape May, New Jersey, where she ditched her SUV in the ocean, WPVI reported.

Once the vehicle was in the water as far as it could go, investigators said, she got out and walked to Wildwood Crest, where police officers took her into custody.

“Strangulation takes time. So this is a brutal murder of a little boy,” Montgomery County District Attorney Kevin Steele said at a news conference on Wednesday.

DiRienzo-Whitehead’s husband found the boy dead Tuesday morning at about 7 a.m., as CrimeOnline previously reported.

According the arrest affidavit, DiRienzo-Whitehead told investigators her son had been “crying all day over the family’s financial difficulties” on Monday. She told them she didn’t want Matthew to grow up “with these struggles,” so after he fell asleep about 9:30 p.m., she strangled him, then drove to Cape May.

Wildwood Crest police officers, told to be on the lookout for DiRienzo-Whitehead after the vehicle was found, were watching the family’s beach home when they saw a woman who matched her description. When they approached and called her name, she told them, “I know what I did.”

Montgomery County, Pennsylvania, detectives and Horsham police questioned her at Wildwood Crest police headquarters, where she is being held until she can be extradited back to Pennsylvania.

Investigators found a men’s black dress belt in the SUV.

Germantown Academy, where Matthew Whitehead was a 6th grader after attending school there since kindergarten, said in a statement that the boy “was an extraordinary child with a smile as bright as the sun.”

“We loved him, and we will forever mourn his loss, a devastating tragedy for our community, his family, his friends, and our world,” the school said. “We will do everything in our power to carry his memory forward, to honor him as he so truly deserves, and to live our lives well as a tribute to him.”

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[Featured image: Ruth DiRienzo-Whitehead/Montgomery County District Attorney’s Office and Matthew Whitehead/Facebook]