The city of St Louis filed a lawsuit Wednesday against the NFL over the Rams’ relocation to Los Angeles, alleging the league violated its own relocation guidelines and enriched itself at the expense of the community it left behind.

The move comes 15 months after the team departed. St Louis is joined in the lawsuit by St Louis County and the region’s sports authority. The lawsuit filed in St Louis circuit court names the NFL, all 32 teams and their owners, and seeks unspecified but “extensive” damages and restitution.

The NFL says there is “no legitimate basis” for the lawsuit. A spokesman for the league, Brian McCarthy, said it worked diligently with local and state officials in a process he calls “honest and fair.”

The Rams moved from Los Angeles to St Louis prior to the 1995 season, lured in part by a new taxpayer-built domed stadium. Stan Kroenke, a real estate billionaire and native of Missouri, was minority owner of the team until purchasing it outright in 2010, two years after the death of longtime majority owner Georgia Frontiere.

The suit claims that it wasn’t long afterward that Kroenke began plotting a move, despite public comments from him and team executive Kevin Demoff that the Rams hoped to remain in St Louis for the long term.

“In the years leading up to the Rams’ relocation request, Rams officials decided to move the team and confidentially determined that they would be interested in exploiting any opportunity to do so,” the lawsuit states.

The lawsuit notes that since St Louis officials weren’t aware a move was essentially a done deal, they spent millions of dollars developing plans for a new riverfront stadium project aimed at retaining the Rams.

“The Rams never intended to engage in good faith negotiations with St Louis,” the lawsuit says.

In February 2014, Kroenke bought land in Inglewood, California. According to the lawsuit, Demoff said it was “not a piece of land that’s any good for a football stadium” when asked about the purchase.

“The size and the shape aren’t good for a football stadium,” Demoff said then.

But the lawsuit notes that after league owners approved the move in January 2016, Demoff told an interviewer he recalled Kroenke calling him after inspecting the California property in 2013 and saying it was “an unbelievable site” for a football stadium. The lawsuit says Demoff said the call was one of the “moments in your life you never forget.”

The Inglewood stadium is expected to open in 2019. The Rams are playing at Memorial Coliseum until then.

The NFL adopted relocation guidelines in 1984. The lawsuit claims the league violated those guidelines “and instead focused solely on whether more money could be made in Los Angeles – a factor which does not justify relocation under the policy,” the lawsuit states.

The lawsuit alleges that while the league has enriched itself and its teams with the move, St. Louis has lost an estimated $1.85m to $3.5m each year in amusement and ticket tax collections, as well as roughly $7.5m in property taxes. In total, the city will have lost more than $100m in net proceeds, the suit alleges.

The lawsuit is among several filed over the Rams’ departure. Three separate lawsuits related to personal seat licenses were consolidated into one suit. Another suit filed by the regional sports authority seeks to keep the Rams from obtaining the team’s former practice facility in St Louis County for $1 in 2024, as spelled out in the team’s original lease.

The Rams finished 4-12 in their first season back in Los Angeles and haven’t had a winning record in any season since 2003.