The Miami-Dade County Commission on Ethics and Public Trust found probable cause Tuesday that North Miami Mayor Andre Pierre “exploited his position’’ by avoiding thousands of dollars in rental fees when he regularly used a city athletic field for free for pickup games for his soccer club.

A Miami Herald investigation in April revealed that Pierre reserved the North Miami Athletic Stadium for private soccer practice 78 times from October 2009 to September 2011. Based on the city’s regular rates, the rentals would have cost around $29,000.

Additionally, a private soccer club named North Miami Taxpayer’s Soccer Club reserved the stadium 29 times from September 2011 to January 2012, racking up $9,000 in rental fees that were not paid, according to records. Pierre is a member of North Miami Taxpayers Soccer Club.

According to the ethics commission, “Pierre’s group, ‘North Miami Taxpayers Soccer Club,’ used the fields more than 100 times without paying.”

Pierre engaged in this activity even though the North Miami City Council unanimously passed a resolution in April 2010, which established policies for park rentals and limited fee waivers to certain qualified organizations for only one no-cost use per year, the ethics commission found. The commission found Pierre’s use exceeded that criteria.

Typically the city requires $150 for 90-minute day rentals and $250 for 90-minute evening rentals at the stadium, near the entrance of Florida International University’s Biscayne Bay Campus.

In a statement released by the ethics commission, Pierre through his attorney, argued that he was following proper protocol by utilizing the facility for “pick-up soccer games” and said the usage was consistent with “community service” activities of the city.

The case will proceed to a public hearing.