A hulking homeless man was found guilty Tuesday of killing a 6-year-old boy in a Brooklyn elevator knife attack that left the helpless child’s 7-year-old playmate clinging to life.

A jury took a day and a half to deliberate before reaching its verdict against Daniel St. Hubert in the gruesome attack at the Boulevard Houses in East New York on June 1, 2014. St. Hubert, 30, was convicted of murder and attempted murder.

Best friends Mikayla Capers, 7, and P.J. Avitto, 6, were playing tag outside the complex when they decided to go to P.J.’s sixth-floor apartment for Italian ices.

The pair were laughing and playing when a lumbering St. Hubert got on the tiny elevator with them. Prosecutors said he pulled out a steak knife and went after the kids, stabbing Mikayla 16 times and P.J. 11 times.

Moments later, Mikayla crawled from the bloody elevator, screaming about what happened to her and the friend she loved like family.

“Someone stabbed me,” she cried, according to witnesses. “A man stabbed me and my cousin.”

The children were rushed to Brookdale Hospital. Mikayla’s lung collapsed. P.J. could not be saved.

Witnesses said they saw a stranger leave the building and fall into a grassy area before taking off. Police searched that area and found the bloody murder weapon. The knife was tested, and blood on it matched the children’s.

Prosecutors said DNA from the scene matched St. Hubert, who was placed near the crime scene by witnesses, video surveillance and cell phone records.

“It is impossible to fathom that someone would brutally stab small, innocent children who were going to get some icees after playing in a playground,” Brooklyn District Attorney Eric Gonzalez said in a statement.

“I know that nothing will bring solace to the family of little P.J. and that Mikayla, who bravely took the stand at trial, will carry the scars of that day forever. It is my hope, however, that today’s verdict will still afford them a small measure of closure by knowing that this defendant has been brought to justice.”

Mikayla, now 11, spent nine days in the hospital recovering.

Aricka McClinton, P.J.’s mother, held hands with family as the verdict was read, and cried after the foreman read “guilty” for both charges.

St. Hubert faces 50 years to life in prison when he is sentenced May 15.

His lawyer, Howard Greenberg said he will appeal.

“I believe this case will be reversed on appeal,” he said. “There was too much cheer amongst the jurors. This is not a happy time, no one should be laughing.”