BERLIN (CNN) -- Authorities in southwest Germany were looking for a motive Monday in an apartment building fire and a hospital shooting that, together, killed four people and are believed to be linked.

Two bodies -- one of a man and another of a 5-year-old boy -- were found inside a burning building in the city of Loerrach, police said Sunday evening.
As authorities responded to the fire, they saw a woman -- armed with weapons -- run from the building toward a hospital.
On the way, the woman -- later identified as a 41-year-old lawyer -- shot two passers-by, severely wounding them, police said.
At the St. Elisabethen hospital, the woman stabbed and shot a male nurse, killing him before police fatally shot her, authorities said.