Columbia Sportswear Company has added clog maker Crocs to a lawsuit it has filed against a former employee accused of designing shoes for competitors.

According to a court filing emailed to just-style by Columbia, its former lead footwear designer Brian O'Boyle allegedly performed design services for 'several competitors of Columbia'.

Columbia's filing, with The Circuit Court of The State of Oregon, claimed his designs "incorporate Columbia's trade secrets and are visually similar to Columbia designs".

News of the potential court case first arose in August, but only O'Boyle was accused at that time.

This week's ammended filing includes allegations about Crocs too though, saying the company had "actual knowledge" he was employed by Columbia.

Columbia claims that four models that O'Boyle helped design are still being sold by Crocs.

Crocs spokespeople were not immediately available to comment on the allegations when contacted by just-style today (10 December).