Back in January, a lobbyist for Chicago Mayor Brandon Johnson estimated that the city would need up to $76 million to pay for overtime, salaries and equipment for Chicago police providing security at the Democratic National Convention, according to emails obtained by NBC 5 Investigates.

The email exchange between the then-Johnson administration lobbyist in Washington DC and a congressional staffer revealed that Chicago would spend up to $25 million on overtime for Chicago police, another $10 million on salaries and $25 million on equipment, including a new helicopter, body cameras and additional items such as renting vans and body armor.

The email history also shows that the request for a $76 million Justice Department grant “exceeded all previously requested grant amounts.”

As part of his email thread, the lobbyist also shared a Politico article highlighting a clash between pro-Palestinian protesters and police in Washington DC.

The congressional aide responded, “That is precisely why we are making this funding a top priority.”

A spokesman for Johnson and the city’s budget office said there are no cost estimates for the DNC and it could take a week or two to get them.

Additional security cameras and fencing were installed after protesters breached a portion of the fence in the north security perimeter about two blocks north of the United Center, where the DNC was taking place.

“That really concerns me. There’s just a lot of money involved,” said Freddy Martinez of the Lucy Parsons Lab, which has been studying police surveillance technology and equipment for years. “It raises questions about how these decisions are made. And do citizens have any say in how we want to see our city in the future? That’s a big concern for us.”

NBC 5 Investigates interviewed Chicago Police Chief Larry Snelling about the costs and criticism.

“So, first of all, I know I don’t care about the finances, so I’m going to leave that part alone. But I can tell you one thing: If it’s necessary to keep the city safe, you have to make the investment. When we see police officers putting their lives on the line every day, police officers putting their safety at risk every day, leaving their families at home, then the investment in keeping this city safe is absolutely necessary,” Snelling said.