The US Marshals FugitiveTask Force caught 31-year-old Isaiah Reels in Southwest Philadelphia earlier this week.
Police say Reels, and 39-year-old Nelson Giddings, shot the 65-year-old Harris after breaking into her Powelton home.
Giddings was arrested last month.
Both are facing a number of charges, including murder, robbery, and burglary.
Police believe the men meant to target a different home and shot Harris when she confronted them.
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