In spotlight at Labor Espionage Investigation. Washington D.C. E.C. Davidson (left), Secretary of the International Association of Machinists and Mayor of Alexandria, Virginia, who told the Senate Civil Liberties Committee today that the Pinkerton Detective Agency sought to sell it's service to the Committee to Investigate Other Labor Espionage Agencies. Davidson also said that Samuel X. Brady, of Pinkerton Agency, had contacted him (Davidson) in regard to acting as a go between. In the center is William D. Whitney, Councel for the Pinkerton's, who informed the committee that his agency would refuse to disclose the requested names of undercover agents. On the right is Robert F. Pinkerton, President of the Detective Agency