When you let a killer into your store, it's probably not a good thing.

Shares of Kohl's Corp. (KSS - Get Report)  finished only 1% higher after the department store operator announced Tuesday that it will accept returns on select merchandise purchased on Amazon.com (AMZN - Get Report) in 82 of its stores located in Los Angeles and Chicago, according to Reuters. Shares had been up as much as 5%, but gave back some gains as investors speculated Kohl's would be hurt by a deal with the wrecker of bricks-and-mortar retail. 

When the program begins in October, Kohl's will package and transport all returned Amazon items to the ecommerce giant's return centers. This move follows Kohl's decision earlier this month to sell Amazon devices such as the Echo smart speaker at 10 stores in Chicago and L.A.

Kohl's joined Sears Holdings Corp. (SHLD) in teaming up with Amazon ahead of the holiday season as the online retailer puts a major dent in brick-and-mortar sales. It's also further evidence of Amazon's venture into retail locations following its acquisition of Whole Foods Market and its 456 stores.

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