NEW YORK (CBSNewYork) – Federal investigators are probing an explosion that critically injured a 73-year-old landlord in Queens Friday afternoon.

As CBS2’s Ali Bauman reported, a tenant said he noticed the package on his doorstep earlier in the week but just put it to the side because he didn’t recognize the name it was addressed to.

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Police said the package sat in front of the home for days until the victim came by and opened it.

Elderly Landlord Severely Burned When Mysterious Package Explodes In Springfield Gardens, Queens

Cell phone video captured the elderly man doubled over in pain after he opened the mysterious package left on his 222nd Street porch.

“I heard a loud explosion,” Spring Gardens resident Rick Thomas said. “It shook the house.”

Thomas was one of several neighbors who threw wet towels to the victim.

“I saw a man lying in the grass and he was actually on his knees and he was on fire,” Thomas said. “He was screaming out in pain. Lot of pain, because the flames engulfed his whole top half.”

“He was burned all over his body from head to toe,” neighbor Audrice Campbell said.

The bomb squad spent the next several hours collecting evidence and testing residue on the brick wall and front door of the home. They found a cylinder-shaped package roughly the size of an oatmeal box filled with black powder — possibly gunpowder used in antique firearms.

Detectives called it a low grade explosive.

“There was substantial evidence left from this device which appears to be a victim actuated device, in other words when he opened it the explosion occurred,” Chief Robert Boyce said.

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Saturday morning, the building’s tenants said the package appeared several days ago.

“I don’t think they were trying to target me because the name wasn’t my name, it wasn’t anybody’s name that’s why it was rather fishy,” one tenant said. “I didn’t want to move it because we’re pretty much, Haitian, and it’s a French name that was on the package, that’s why I didn’t call the landlord. I thought it was somebody who just moved in, because we have some new tenants on the basement.”

“I have a little girl. So it’s like, we’re all scared. Even thinking of trying to find another place, to get out,” he added.

Kathleen Toussaint also rents the home, and said the package had been sitting on the porch for about a week.

“Whenever they deliver packages, if it’s not for one of us we usually just leave it here and then usually the USPS just pick it up and they return it to the sender,” she tells WCBS 880’s Kelly Waldron.

She said the landlord passes by every day and must have seen it earlier in the week.

“I guess he realized it was still sitting there so he decided that he wanted to open it I guess,” Toussaint said.

A man named Cornelius told 1010 WINS’ Roger Stern the incident made him so upset that he’s moving out.

“I see him on his knees like that, I mean it looked like he had mud, like he was covered in mud or something,” he said.

The landlord remains in the hospital in critical condition with second degree burns covering 80 percent of his body.

Police say while the package had no postal information, it was addressed to a first name.

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Anyone with information in regards to this incident is asked to call the NYPD’s Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74682). The public can also submit their tips by logging onto the Crime stoppers website at WWW.NYPDCRIMESTOPPERS.COM or by texting their tips to 274637 (CRIMES) then enter TIP577.