A Florida judge has stepped aside from a Federal Election Commission lawsuit accusing a former Republican congressman of secretly funneling thousands of dollars to a little-known Democratic candidate in 2012.

Miami U.S. District Judge Robert Scola recused himself Monday after the lawyer for ex-Rep. David Rivera said the judge appeared biased based on his handling of a related criminal case. Scola denied bias in his order but stepped aside anyway, and another judge will oversee the case.

The lawsuit claims Rivera illegally contributed $69,400 to Justin Sternad in an attempt to weaken the rival Democratic campaign of Joe Garcia, who eventually won the seat. The lawsuit seeks more than $480,000 in penalties.

Sternad and Rivera associate Ana Alliegro pleaded guilty to criminal charges in the scheme. Rivera was never charged.