A Denver-area man missing in the Sri Lanka Easter Sunday terror attacks targeting Christians and luxury hotel guests was confirmed dead by his brother on Monday, according to a report.

40-year-old Dieter Kowalski traveled to Sri Lanka early Sunday morning for work, checking into the Cinnamon Grand Colombo hotel at 3:45 a.m. local time. The hotel was bombed roughly five hours later in one of eight blasts targeting churches and other hotels that killed around 300 people and injured hundreds more.

“It is with great sadness and deep regret that as Dieter’s brother that I confirm that Dieter was among the victims that passed away in Sri Lanka,” Dieter’s brother wrote, according to the Daily Mail. “As we know that Dieter saw his friends as family, we would like to share our grief over this tragic incident. More information to follow. We have all lost a brother today… RIP Dieter.”

Kowalski reportedly worked for a technology company. Further details about the Denver man are presently unknown.

Two Americans with dual citizenship of the US and UK were among 11 foreign nationals killed, Sri Lanka’s foreign ministry confirmed.

One of Cinnamon Grand hotel’s manager told reporters that the suicide bomber set off a bomb around 8:30 a.m. local time after standing in line at the hotel’s breakfast buffet. The manager said the bomber checked into the hotel the night before as Mohamed Azzam Mohamed.

“There was utter chaos. It was 8.30am and it was busy. It was families,” he said. “He came up to the top of the queue and set off the blast. One of our managers who was welcoming guests was among those killed instantly.”

Sri Lanka Health Minister Rajitha Senaratne said Monday that a local Islamist terrorist group called “National Thowfeek Jamaath” is responsible for the deadly bombings.