Prosecutors in the state capital Erfurt say the children's mother came home from a hospital stay today to find her three sons with serious injuries.
The 1-year-old and 4-year-old sons subsequently died, while a 3-year-old is in a critical condition.
German news agency dpa reported that the 27-year-old man was also present in the home in Altenfeld, about 200 kilometers (124 miles) east of Frankfurt.
The suspect was arrested and is in a hospital receiving treatment for self-inflicted wounds.
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