BERLIN — DNA tests on three girls born between 2015 and last year and found abandoned on the outskirts of Berlin showed that they were sisters, the authorities confirmed on Tuesday.

The police in Berlin are now appealing for information about the mother of Emma, Lilo and Hanna, who were all abandoned just hours after they were born around the city’s Pankow neighborhood. Police named the girls, who are now in foster care, local media reported.

“It’s certainly the same mother,” said Michael Maass of the Berlin Police. “And we are going on the assumption that it is probably the same father.”

All three girls, who were born about a year apart, were found around the Helios Clinic in Berlin-Buch, some 15 miles northeast of the capital’s center. But the way the umbilical cords were cut indicated that the births had not taken place in a hospital. The babies were probably delivered without medical help, according to police experts.