CHARLOTTE, N.C. — Charlotte leaders rubber-stamped millions of dollars more in taxpayer spending this week to the same company accused of overcharging the city just three months prior.

HNTB, the construction management company in charge of the Blue Line Extension project, received up to $4.2 million more to finish the job Monday night. City councilmembers approved the additional funding without any discussion despite an audit earlier this year that questioned unnecessary payments to the company.

Earlier this year, a city audit found Charlotte taxpayers overpaid HNTB by at least $1.6 million. The city is still considering its options when it comes to recouping some of that money. Campaign finance records show the company's political action committee has a long history of donating to local leaders, including half of the current City Council.

In May, we learned HNTB has nearly $90 million worth of contracts with the city in all and discovered HNTB previously faced questions of inflated costs and improper billing in Texas and New Jersey.

As a result of our questions, Councilmember Tariq Bokhari requested a widespread audit Friday of all HNTB city contracts.

"It's hard for us to see every single little detail. There's so much coming at us, so when folks like you go out there and find little details that could end up being big things, it's important," he said. "I've had staff kind of scramble around a bit and right now the city auditor is in communication with several different departments that have touchpoints with this vendor and different contracts and they're pulling together that entire view and they're going to rescope what will potentially be a comprehensive audit."

The Blue Line Extension opened more than a year ago, but all of the work is not complete. City records show delays are the reason HNTB now needs up to $4.2 million more to wrap up the project.

After we first reported the problem, the mayor and councilmembers promised better oversight moving forward, but at Monday's meeting, no one addressed the request for additional money. It was lumped together as a formality with more than a dozen other items, a few of which received discussion, and ultimately passed unanimously.

We reached out to every councilmember Thursday asking for comment. After we started asking questions, city staff sent councilmembers talking points about the topic.

Councilmember Bokhari, who has not received campaign donations from the company, said he's since learned city staff thought it'd be too complex and costly to swap out vendors at this point in the project.

"I went and kind of asked the follow-up questions," he said. "Aside from the challenge that we've had with them recently, everything seems to be going fairly well, so this seemed to be a logical conclusion that they jumped to."

While he's comfortable with Monday's decision, he said he stil has questions about those other contracts we found and he's hopeful a full review of all HNTB business will ensure more taxpayer money isn't wasted.

Even with the new approved funding, the city said the Blue Line Extension project still remains under budget.

Mayor Pro Tem Julie Eiselt is the only other councilmember to acknowledge our questions. However, she said she was in Raleigh for a state meeting.

Charlotte Area Transit System declined our request for an on-camera interview.

HNTB has also not yet responded to our request for comment.