A man who killed his 60-year-old girlfriend and stabbed her 9-year-old granddaughter before starting a fire in their apartment has been sentenced to 17 years in prison, prosecutors say. 

Henry Maldonado, 58, of the Bronx, was sentenced Tuesday after pleading guilty to first-degree manslaughter and second-degree attempted murder in January, the Bronx District Attorney's office said. 

"The defendant mercilessly stabbed the victim and her young grandchild in the Bronx apartment they shared," District Attorney Darcel Clark said in a statement. "We hope the sentence he received today will help the deceased victim's family to heal, especially the brave, resilient young girl who survived and recovered from the horrific attack." 

Maldonado woke up the girl and her grandmother, Carmen Irizarry, at their eighth-floor apartment in the St. Mary's Houses on East 156th Street sometime before 5 a.m. on May 11, 2016, according to the NYPD. An argument allegedly led to the stabbings.

The girl was stabbed in the chest, abdomen, thigh and armpit, but managed to run out of the apartment, police said. Irizarry was fatally stabbed several times, and the man appeared to have stabbed himself as well. 

The girl ran up to neighbor Loretta Fleming's apartment on the ninth floor and banged on the door. Fleming said that she answered, saw the girl "full of blood" and took her in. 

"She's like, 'My grandfather went crazy. Please help me, help me,'" Fleming said at the time. 

Fleming called 911 as the girl cried that Maldonado was going to come upstairs and attack her again. 

"She said, 'Oh he's going to come up here to get me, he went crazy,'" Fleming said.

Police responded to the scene and knocked on the family's door, according to the NYPD. They didn't get an answer but heard a male voice inside, so they called supervisors and the department's Emergency Services Unit to get the man out.

Sometime after police arrived on scene, authorities say a fire was set in the apartment's living room. Firefighters were also called to the scene and extinguished the flames. 

The NYPD said that ESU officers then went inside the apartment and found Maldonado holding a knife. They ordered him to drop the weapon and stunned him when he didn't obey the order.

Maldonado was pulled out of the apartment and taken into custody, police said. The grandmother was pronounced dead in the living room. 

The 9-year-old girl was taken to the hospital for treatment.