A 12-year-old boy now is facing more serious charges after allegedly throwing a kitten against a wall and beating it with a stick, causing injuries that ultimately led to its death.

The youth initially faced a misdemeanor animal cruelty charge. It has been upgraded to felony animal cruelty after an examination showed the kitten died of injuries from the attack.

Animal Control officers responded to the 900 block of Brook Avenue on May 28, where a group of children said they had been playing with the 7-week old stray and that the accused had grabbed the kitten and thrown it against a wall. He then began to beat the kitten with a stick before pulling out a pocketknife and saying he would cut it, Suffolk spokesperson Debbie George said.

That’s when 9-year-old Jamarea Mills knocked the knife out of the boy’s hand.

The male kitten — dubbed “Little Heart” because of a heart drawn on the leg cast it received once it was rescued and taken to the veterinarian — survived for about five days.

While under the care of a foster family and awaiting adoption, the kitten began having trouble breathing in the middle of the night. It was rushed to an emergency veterinarian but died shortly after arriving.

Veterinarians initially diagnosed the kitten with a broken leg and bruises to its lung and abdomen area, but the examination revealed the injuries were more serious than originally suspected, George said Tuesday.