With 11 fatalities, Saturday's fire was the worst such disaster in the Czech Republic since 1990.
The fire broke out in an apartment in the north-eastern town of Bohumín shortly before 6 p.m. Firefighters arrived just five minutes after receiving an emergency call.
Six people, including three children, died in the flat - five others after jumping from the 11th floor to escape the fire.
Some witnesses have criticized the firefighters who arrived just minutes before people jumped out of the window. However, the fire department and also the Minister of the Interior Jan Hamáček (ČSSD) rejected the claims that their intervention took too long.
Police detained a 54-year-old man who confessed at the scene that he intentionally set the apartment on fire. He cited family disputes as his motive. Supposedly, his wife, son and grandson were all in the apartment at the time of the fire. Police accused the man of murder and endangerment - he could face a life sentence.