Police and public prosecutors are busy investigating the father of the Hanau assassin.

The man is said to have repeatedly violated a judicial approach prohibition.

In the meantime, investigations into suspected violations of the Violence Protection Act have been initiated in 21 cases, as well as three further investigations into suspected resistance to law enforcement officials, the Hanau public prosecutor said on Tuesday in response to a dpa request.

The man was also temporarily taken into police custody last week.

With the custody, a place reference should be enforced, as a police spokesman said.

Several media had previously reported about it.

The man is said to have stayed near the apartment building where the mother of one of the victims of the racist attack of February 19, 2020 lives.

Victim's relatives called "wild strangers".

In this context, the public prosecutor's office had previously investigated the man on suspicion of stalking and threats, but the proceedings had already been partially discontinued.

However, the suspicion of a violation of the Violence Protection Act remained, the authority said.

The man is the father of the 43-year-old German who shot nine people in Hanau on February 19, 2020 for racist reasons and then killed his mother and himself.

In September, the father was sentenced to a total fine of 4,800 euros in an appeal by the Hanau Regional Court for insult in two cases.

In a further charge, the court overturned a first-instance judgment of the Hanau district court and acquitted him of the charge of insult.

Among other things, the man had in a criminal complaint described people who had taken part in a demonstration near his home - including relatives of the victims of the attack - as "wild strangers".