It happened Friday afternoon on the 1200 block of Vine Street.
"He was only in his undergarments. His face was bleeding and he was yelling for help," said Captain John Walker, Philadelphia Police Department.
As he was yelling a Philadelphia police detective was driving by and stopped to help.
The victim, in his 50s, told the detective that the thieves ran towards 13th Street and the detective ran quickly after.
"I saw the two guys walking through Pearl Street. I almost got ran over by them," said Alex Simcox.
The two ended up at the Goldtex Building, which is still under construction.
Security personnel saw them both.
"He tried to act like he was working here," said Brian McDuffie, security guard.
"He ran through here, he had a wallet in his hand. He came down like this, dropped the wallet and he leaped down into the basement and disappeared," said Ron Reynolds, security guard.
"I went in the basement and found the second guy," added McDuffie.
Police arrested both suspects, found the gun, the wallet and the clothes they allegedly took.
The victim, who was hit with a .38 caliber gun, was taken to Hahnemann Hospital with several facial injuries.
"He was definitely struck with the gun multiple times inside the home, we believe in the basement. They took his clothes and phone so that he wouldn't chase them out of the property," said Capt. Walker.
"He had a bandage on his face. He didn't have pants on. He was really banged up," said Simcox.
Meanwhile for those living and working in the neighborhood, many are breathing a sigh of relief.
"After I saw the guy who got robbed, I'm just happy I wasn't a part of it," said Simcox.
"They got 'em, thank God for the Philadelphia Police," said McDuffie.
Meanwhile both suspects remain in police custody, acing a number of charges.