The House on Thursday took the extraordinary step of empowering an internal panel to take witnesses into custody, including one of its own members while he serves a six-month sentence for assault. The step comes as lawmakers try to force Representative Carlos Henriquez’s resignation.

The House adopted an order giving its Ethics Committee the power to issue a writ of habeas corpus ad testificandum in connection with a complaint received on Jan. 15, the day of Henriquez’s conviction. Last week, the House gave the Ethics Committee subpoena powers.

The Dorchester Democrat was convicted and sentenced last week for two counts of assault and battery against an Arlington woman he had been dating, stemming from a July 2012 incident.

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Thursday’s maneuver raises the prospect of an outlandish spectacle on Beacon Hill: a state lawmaker returning to the State House as a prisoner serving time.

House leaders had hoped Henriquez would resign without formal action by the body. His attorney, Stephanie Soriano-Mills, said Tuesday that Henriquez had not decided whether to step down, and has said that he plans to appeal the conviction.

Following his conviction on Jan. 15, the second-term lawmaker was promptly sentenced to two and a half years in the Middlesex County House of Correction, with six months to be served behind bars. On Jan. 16, the House authorized the Ethics Committee to subpoena Henriquez, the first step in a process that could result in Henriquez’s expulsion from the body.

Governor Deval Patrick, House Speaker Robert DeLeo, and Boston Mayor Martin J. Walsh all called for Henriquez to resign after he was convicted last week, and DeLeo said the House would move to expel him otherwise.