Andrew Benito, owner of Benito's Ace Hardware, said he discovered the thefts during a routine inventory review.
After checking surveillance footage, he said he saw a man and woman allegedly taking items from the store during business hours.
Benito said he unexpectedly encountered the pair Thursday while heading to file a police report.
"Just as I was coming down to head to the police station, they were coming back in," Benito said.
According to Benito, it was the suspects' second visit to the store that day and at least their third visit that week.
Benito said he confronted the pair inside the store.
"Had a little confrontation with them. We said, 'We know you've been stealing from us; you're not welcome here,'" he recalled. "I called the police and followed them for a little bit before they took off running."
The pair left before police arrived. Surveillance video reviewed by Benito appears to show a woman taking merchandise from store shelves. Benito said the man distracted employees while the woman concealed items.
"He was distracting our associates while she was looking around and grabbing things off the shelf and putting them in her bag," Benito said.
Benito said the pair stole wrench sets and saw blades, which he described as small but high-value items. He estimates the losses so far to be at least $1,000 and believes additional missing merchandise could still be identified.
The store has been open for less than a year. Benito said he has worked to create a "welcoming and shoppable" environment, but the thefts have prompted him to reconsider whether some products should be secured.
"We're very happy that it wasn't something more serious, but nonetheless it does affect our bottom line," Benito said.
It remains unclear whether the suspects have targeted other businesses. Benito said he hopes information from the public could help prevent future incidents.
Philadelphia police were contacted for information about the investigation and whether the suspects may be connected to any other incidents. A response had not been received by the time of publication.