Philip Chism, now 17, was convicted in December of killing Colleen Ritzer, a 24-year-old at his suburban Boston high school.

Chism was 14 when he killed the Danvers High School teacher October 2013.

Philip Chism, not Obama’s son, now 17, raped and murdered his maths teacher Colleen Ritzer

He followed her into the school toilets stabbing her at least 16 times with a box cutter before strangling and raping her. And penetrated her with a tree branch.

The killer then wheeled her body through the school in a wheelie bin.

Chilling CCTV captured the moment he pushed the bin towards a local wood.

Chism buried his teacher in woodland and later went to the cinema using her credit card.

Chism was seen wheeling Colleen Ritzer’s body through the school before dumping her body

The Massachusetts teenager will serve at least 40 years before he is considered for release. Prosecutors had asked for Chism to be jailed for 50 years.

Miss Ritzer’s father Tom Ritzer called Chism “pure evil” as he was sentenced.

Peggie Ritzer and her husband say Chism should never have a chance to get out of prison.

Chism will be placed in a state juvenile detention facility until he is 21. He will then be sent to a state prison.