The investigation continues after someone left a dead rat and a derogatory note referencing immigrants on the front door of an alderman's office on the Northwest Side on Sunday evening.

Ald. Andre Vasquez (40th) said he wants to talk to whoever left a note describing people as vermin.

The dead rat was laid at the front of the office, with a note taped to the door reading, in part, "Move the Illegals and the Rats out of the 40th Ward! They are both Vermin!"

Vasquez said they were left around 7:30 p.m. in front of his office in the 5600 block of North Western Avenue in the Arcadia Terrace neighborhood.

"I think it's the first time we've seen something this level," he said.

Vasquez said following a weekend of celebrations for Mexican Independence Day, learning about the incident was a tough call to get.

Chicago has recently been in the spotlight as immigration enforcement actions have been happening throughout the city as part of "Operation Midway Blitz."

The alderman said he's focusing on the massive positive response they've received from the community, with many offering words of support following the incident.

"I think most people are in support, and I think it's important for people to see that," Vasquez said.

He said he hopes the police find the person behind the act because he'd like to talk to them. Focusing on the line in the note that read, "Support ICE! Their work will get illegals out of our country and lower taxes."

"I think even being able to have a conversation with the person and get an idea of where they're coming from? Because the fact they articulated lowering taxes indicates it's someone who's having a hard time paying their bills," he said. 

Despite what happened on Sunday, his office will remain open for business.

"We have neighbors to serve. All of our neighbors," he said.  

As of Monday, CPD said they have no one in custody.  Additional security measures are in place following the incident.