Dobbs said at a press conference Wednesday.
Dobbs said the tip came in "several weeks ago" and was known by only the top brass in the department. He declined to say where the tip came from or the nature of the tip, deferring questions about the investigation to the state's Department of Criminal Investigations.
Dobbs' comments came during a press conference led by City Administrator Ben Hughes. City Attorney Rob Weber also spoke.
It was clear from the press conference and comments afterwards that everyone in the city is bracing for Becker's prolonged absence (if not departure).
Under state statute, City Council President David Maack is now acting mayor of the city. He'll fill that role until Becker returns, resigns or the City Council removes him from office.
As acting mayor, Maack will sign official city documents, run City Council meetings and fulfill all of the ceremonial roles that come with being mayor.
Weber said it was too early to discuss the process for removing Becker, but did confirm the council could do so before a criminal conviction. Three-quarters of the council members would have to vote to remove Becker.
"At this point in time, Gary Becker is still the mayor," Weber said. "There is a presumption of innocence."
Hughes said city government would continue to operate without Becker in charge.
"City government will continue to function," he said. "Streets will be plowed, garbage will be picked up. Services will continue to be delivered."
If criminal charges are filed against Becker, he will be represented by his own attorney at his own expense, Weber said. The city will not pay his legal fees.
Weber said he spoke with Becker's family. "The family is shocked," he said.
City officials started hearing about Becker's arrest at 12:30 a.m. Wednesday morning. Maack was notified first, and then called members of the City Council.
Hughes received a call from the Racine Police Department with the news around the same time.
Two aldermen attended a press conference on the arrest. Alderman Greg Helding said he met the news with "stunned silence" after getting the call from Maack.
The shock aside, Helding said he was preparing to move forward with city business. While the city needs a mayor in the long term, in the short term it will run smoothly, he said.
Alderman Aron Wisneski said he was stunned by the news. "It doesn't make sense," he said.
But he added this was an opportunity to show city government is about more than the mayor's office.
"Not all of city government is driven by one man's personality," Wisneski said. "It's a democratic, collaborative process."