Sempra Energy (SRE) said Wednesday it is investigating the conduct of an employee ensnared in a scandal linked to taped sex comments made by a California lawmaker during a legislative hearing.

State Assemblyman Mike Duvall, a Republican from Orange County, resigned Wednesday after a Los Angeles television station aired a videotape of sexual comments Duvall made to a colleague during a legislative hearing in July. The report, by KCAL, said two women with whom Duvall is quoted in the videotape saying he was having an extra-marital affair, are lobbyists at the state capitol in Sacramento, and that one of the women represented large utilities including Sempra.

Duvall was vice chairman of the state Assembly Utilities and Commerce Committee.

Sempra said in a statement that it "takes very seriously any reports involving the conduct of our employees" and is investigating the matter.

KCAL said it retrieved the videotape from the in-house television station used by the state Legislature and that Duvall made the comments apparently unaware that a microphone where he was sitting was turned on.

- By Cassandra Sweet, Dow Jones Newswires; 415-439-6468; cassandra.sweet@dowjones.com