Updated: 9:59 p.m.

House Oversight and Government Reform Committee Chairman Darrell Issa announced Thursday that he will investigate the allegations that D.C. Mayor Vince Gray offered a quid pro quo to a former mayoral candidate.

The California Republican said in a statement that he is “deeply concerned” by former mayoral candidate Sulaimon Brown’s allegations that Gray’s campaign paid him and told him it would secure him a job in the Gray administration if he stayed in the Democratic primary last year and attacked then-Mayor Adrian Fenty.

The Washington Post first reported those accusations.

Issa said committee investigators have spoken with “individuals inside and outside the District government” and have unsuccessfully tried to contact “key figures close to the mayor,” including Gerri Mason Hall, Gray’s chief of staff who resigned Wednesday.

“The initial findings of these efforts do not give me confidence that the District government can make this evaluation,” Issa said. “As such, the Oversight and Government Reform Committee has begun a full investigation to determine the facts and will report its findings.”

In a statement announcing Hall’s resignation Wednesday, Gray said he hoped it would end the distractions.

“The distractions of the past few weeks have overshadowed the important work of this government,” Gray said. “We have agreed that this decision is in the best interest of the city.”

He named Paul Quander, deputy mayor for public safety and justice, to serve as his acting chief of staff.

In an interview earlier this month, Gray said this controversy and another centering on an expensive SUV lease should give no ammunition to Congressional opponents on D.C. autonomy.

The mayor’s office released a statement sticking to that view, saying that Gray will cooperate with Issa but noting that he has already requested that the District of Columbia’s attorney general investigate Brown’s claims.

“Mayor Gray believes that there are sufficient investigative bodies, including the Federal Bureau of Investigation, addressing and responding to Mr. Brown’s allegations. Congressional involvement is not likely to illuminate any additional issues or information,” the statement said. “Although the Mayor, in his support for the autonomy of the District of Columbia, does not encourage congressional oversight of city matters, he and his administration will cooperate fully with this investigation.”

Del. Eleanor Holmes Norton (D-D.C.), a member of the Oversight and Government Reform Committee, released a statement blasting Issa’s decision.

“I am outraged that a congressional committee with a full agenda would make a detour to investigate a purely local matter. There is no congressional issue at stake in a probe of local matter,” Norton said in the statement. “A congressional investigation would take the new House Republican majority’s obsession with invading the District’s home rule to a new low.”

Norton said she wants to meet with Issa to ask him to reconsider.