CPR was performed on both children after being pulled from the south Minneapolis lake.
The vandalism spree dates back to March 25.
The most recent incident happened on Thanksgiving.
The 89-year-old woman says she doesn't feel secure in her home anymore.
The event that attracts thousands every year is going virtual for the pandemic.
It's the third death from a series of incidents over two days in Minneapolis.
Swimming season has ended so no lifeguards are on duty.
The late July, early August outbreak has impacted dozens.
Both the 50th Street and Main beaches are closed indefinitely.