(WASHINGTON) -- Two Wisconsin residents have died following a lightning strike near the White House on Thursday night, police confirmed to ABC News Friday.
Police said 76-year-old James Mueller and 75-year-old Donna Meuller, both from Janesville, Wisconsin, died after being injured in the strike in Lafayette Park in front of the White House.
Metropolitan Police Department Chief Robert Contee confirmed Friday that the Muellers were married and Madison.com reported they were in Washington to celebrate their 56th wedding anniversary.
Thursday night, D.C. Fire and EMS said it had responded and was treating four patients that were found in "the vicinity of a tree."
It said the two men and two women were transported to area hospitals with "life-threatening injuries."
Officials said it's still unclear what the adults were doing prior to the lightning strike, if they knew each other and why they were in the park.
Uniformed U.S. Park Police officers and members of the Secret Service were also on the scene and immediately rendered aid to the victims, an EMS official said during a news conference.
The National Weather Service had issued a severe thunderstorm warning for the area Thursday evening.
ABC News' Beatrice Peterson contributed to this report.