The presidential bid of Ben Carson, a tea party star who has catapulted into the top tier of Republican contenders, has been rocked by turmoil with the departures of four senior campaign officials and widespread disarray among his allied super PACs.

Carson’s associates described a political network in tumult in interviews Friday, saying the retired neurosurgeon’s campaign chairman, national finance chairman, deputy campaign manager and general counsel have all resigned since Carson formally launched his bid last month in Detroit. They have not been replaced, campaign officials said.

The moves gutted the core of Carson’s apparatus and left the 63-year-old first-time candidate with only a handful of experienced aides at his side as he navigates the fluid, crowded and high-stakes contest for the Republican nomination.

But his campaign has been marked by signs of dysfunction and amateurism, alarming friends and supporters who privately worry that Carson’s sprawling circle of associates and boosters is fumbling his opportunity. And, they argue, the candidate has been nonchalant about the unres