NEW ORLEANS  After nearly a week of silence since his arrest on Monday on charges of interfering with the phones in Senator Mary L. Landrieu’s New Orleans office, James O’Keefe III, the conservative advocate, said Friday that he was trying to determine whether Ms. Landrieu was avoiding constituent complaints.

But Mr. O’Keefe acknowledged that he was now thinking twice about his approach.

“The sole intent of our investigation was to determine whether or not Senator Landrieu was purposely trying to avoid constituents who were calling to register their views to her as their senator,” Mr. O’Keefe said in a statement, which appeared on the Web site biggovernment.com.

The site is run by Andrew Breitbart, who played a role in bringing Mr. O’Keefe to national attention by releasing videos in which Mr. O’Keefe secretly recorded members of the community group Acorn giving him advice on how to set up a brothel. Mr. Breitbart also pays Mr. O’Keefe for the rights to his projects.

Image James O'Keefe III said he had misgivings on his approach. Credit... Patrick Semansky/Associated Press

Tea Party advocates and opponents of a health care overhaul complained late last year that they could not get through to Ms. Landrieu’s office or leave messages on her voice mail in the most contentious weeks of the health care debate.