In a little-noted lawsuit filed in May, the Boston engineering firm Howard/Stein-Hudson Associates, Inc. claimed to be owed $446,096, plus ongoing interest, for "thousands of man-hours" of work performed under contract with the Grand Prix. The engineering firm last month secured a court order, running to June 28, to freeze Grand Prix assets, arguing that "the plaintiff is in a race with other creditors to secure assets of the defendant," according to court documents.

In the two months since race plans collapsed, at least three lawsuits have been filed — and more are threatened — against Boston Grand Prix LLC, the local entity that in 2015 signed a deal with Mayor Martin J. Walsh for up to five annual IndyCar races in Boston.

A failed effort to bring a high-speed IndyCar event to the Seaport this fall has led to another kind of race, driven by lawyers, chasing whatever assets remain of the Boston Grand Prix.

That race for assets has drawn a big field.


The national IndyCar organization that governs the sport sued the Boston Grand Prix for breach of contract and is seeking damages.

A one-time sponsor of the Boston race, Global Partners LP, the parent company of the Alltown Market convenience stores, filed suit last Friday against Boston Grand Prix in Essex Superior Court, according to records. Alltown was a sponsor of the Grand Prix's "Freedom Friday" event, which was to include a ticket giveaway to veterans, active military members, and first responders around New England, according to a statement from Alltown last December.

Billionaire car dealer Herb Chambers has issued demand letters to Boston Grand Prix, and is threatening a lawsuit to recover $100,000 in lost sponsorship money. Chambers was the "official auto dealer" of the race, according to promotional material produced by the Boston Grand Prix.


And then there are the ticket holders — an undetermined number of motorsport fans who never received refunds, and are out — in many cases — hundreds of dollars. Boston Grand Prix, through its lawyer, said two weeks ago that after forwarding $400,000 for ticket refunds, it was out of money.

Attorney General Maura Healey has stepped in, subpoenaing documents from the Grand Prix and from the national IndyCar organization, as part of an investigation into what happened to the proceeds from the ticket sales. She has threatened to bring her own civil litigation on behalf of ticket holders, unless the parties connected to the race come up with a plan to refund ticket money. Healey last week hosted representatives and lawyers from the Boston Grand Prix and IndyCar, and gave them until June 27 to come back with a reimbursement plan.

Boston Grand Prix lawyer and spokesman Michael Goldberg said refunding ticket purchases remains the Grand Prix's priority. "To the greatest extent possible, we're simply trying to keep these lawsuits in a place where they don't interfere with that priority," he said in a telephone interview Monday.

ESPN reported in April that organizers had sold more than 20,000 tickets. General admission tickets were $99 for a three-day pass, and reserved grandstand tickets were $150 to $205, according to figures released by the Grand Prix in March.The race had been scheduled for Labor Day weekend, on a 2.2-mile temporary street course around the Boston Convention & Exhibition Center, with cars that can travel 180 miles per hour.


Howard/Stein-Hudson's lawsuit says that the firm had entered a contract with Boston Grand Prix last December, for transportation planning and civil engineering services. The firm signed two more contracts with the Grand Prix in the spring for additional work, the lawsuit states. One of those contracts was signed April 25 — just four days before Grand Prix president John Casey announced the race would be scrubbed. In canceling the race, Casey accused the city of making unreasonable demands on the promoters. The city, in response, said the promoters were disorganized.

Howard/Stein-Hudson employees drafted construction documents, worked on designs, attended meetings and visits to the site, and performed transportation and environmental analysis, among other jobs, according to the lawsuit. A lawyer for Howard/Stein-Hudson could not be reached.

Mark Arsenault can be reached at mark.arsenault@globe.com. Follow him on Twitter @BostonGlobeMark.