Lakeville police are intensifying their efforts to find two missing teenage sisters, threatening to prosecute anyone found harboring them and calling the lack of cooperation “inhumane.”

Samantha and Gianna Rucki ran away from their Lakeville home in April 2013 amid their parents’ bitter divorce and have been missing ever since. Lakeville Police detective Jim Dronen said there are at least four persons of interest in the case, including the girls’ mother, Sandra Grazzini-Rucki, and her attorney, Michelle MacDonald.

“These are people that know what’s going on who haven’t told us what they know,” Dronen said Wednesday.

In an interview two weeks ago with the Star Tribune, Grazzini-Rucki said she has not seen the girls since February 2013 and denied knowing where they were.

That contradicts the account of former attorney Dale Nathan, who told the Star Tribune that he was with Grazzini-Rucki the day the girls ran away. He said the girls ran from their home to Grazzini-Rucki’s car, and that the four of them drove around for two to three hours that day.

Nathan said Wednesday he will not share any information about that day with Lakeville police.

“As far as I know, Sandra Grazzini-Rucki is trying as desperately as she can to protect her daughters, and I don’t want to be involved in hurting her further,” Nathan said.

Dronen said Lakeville police also consider Michael Rhedin a person of interest. Rhedin, a Hennepin County adult corrections officer and former Elko police officer, is a friend of Grazzini-Rucki.

Nathan said he met with Rhedin the day the girls went missing. The girls’ father, David Rucki, said he saw one of the girls at Rhedin’s home two months later, but she eluded him. Rhedin did not respond to requests for comment for this story.

Dronen said Lakeville police do not know how to reach Grazzini-Rucki. He said he tried to get to her through her attorney, MacDonald. MacDonald’s attorney returned the call, but provided little information, Dronen said.

Last year, MacDonald ran an unsuccessful campaign for a seat on the state Supreme Court.

MacDonald’s attorney, Stephen Grigsby, said his client has no knowledge of the girls’ whereabouts.

“This sounds like an attempt by police to intimidate a lawyer in her legal duty to represent the rights of a client in a custody matter,” Grigsby said.

Three weeks after the girls ran away, they appeared on a Fox 9 news report where they said they wanted to get away from their father.

Dronen said he has called the station to ask where the interview was conducted and was referred to their attorney.

In a Facebook post Wednesday, Lakeville police said: “You would think people would want to cooperate, including attorneys and local television reporters who knew where the kids were, but that is not the case. We cannot force people to talk to us who have retained attorneys.

“Somehow certain people have forgotten these kids will never have their childhood back again and have no remorse for taking it away.”