Residents say Julie Fullmer was the type of mayor who would give out her cellphone number, responding to complaints at all hours about unplowed snow routes or broken sprinklers. She regularly encouraged residents, especially women, to run for City Council and volunteer on boards.

Elected as a councilwoman in 2013 and as mayor four years later, she has helped guide Vineyard’s rapid growth from a farming town of 177 to a city of more than 14,000. She prides herself on a list of accomplishments, including the transformation of a shuttered steel mill into trails, townhomes, housing subdivisions and what developers hope might someday become Utah City — a downtown rivaling that of Salt Lake City.

That venture was supposed to put Vineyard on the map. Instead, it has become the latest point of contention about the mayor’s leadership, according to interviews with nearly two dozen Vineyard officials and residents, as well as a review of campaign disclosures, emails, recordings of Council meetings and community posts online.

Citizens have signed two petitions in recent years calling for Ms. Fullmer, 39, to resign. An adversary on the City Council has demanded scrutiny of her spending. And in elections last month, residents overwhelmingly voted to weaken the mayor’s powers.

Showing a penchant for secrecy, she pledged $5 million in 2020 — without council members’ knowledge — for a controversial lake development project. She has largely self-funded her political campaigns, but residents are in the dark about the sources of her and her husband’s income (her role as mayor is only a part-time job). And recently, her ex-husband came forward to make startling claims about her past.