Mitchell considered the answer in silence. "There is nothing for it but a trip to Front Royal," he said finally. "Go there, Welsh, and find out if Oscar Jackson arrived there to-day on the _three o'clock_ train--no later train, mind you--from Washington. I understood Mr. Rodgers to say that Oscar is from Front Royal and has relatives living in its vicinity. Therefore he is known and I don't anticipate that you will have difficulty in locating him. Keep me informed by telephone." "Very good, Inspector." Welsh paused half way to the door as a thought struck him. "Did you get a message from Mr. Benjamin Potter?" "No. What did he want?" "He didn't say." Welsh again started for the door. "Just asked to have you call him up. Wasn't his wife one of the witnesses at the Baird inquest?" "She was--" Mitchell was already reaching for the telephone directory. "As you go out, Welsh, tell Allen to bring my car around at once." Getting the Potter apartment on the telephone was more difficult than Mitchell expected; the naturalist used a private wire and it was only by virtue of his office that Mitchell was supplied with the number by "Information." Another wait ensued as Central claimed the wire "busy," and it was with perceptible irritation that the Inspector answered the hoarse, "Hello," that finally responded to his repeated calls. "Can I speak to Mr. Potter?" he asked. "Mr. Potter is out--" a violent cough interrupted the speaker. "Is there any message?" "Who is speaking?" "Mrs. Potter." "I beg pardon, Madam." Mitchell moderated his voice. "This is Detective Headquarters--Inspector Mitchell on the 'phone. Your husband left word for me to telephone to him. Do you know what he wished?" "No." The curtness of her tone annoyed Mitchell. "When will your husband return?" he asked, raising his voice. "Very soon, I imagine." There was a pause, and Mitchell concluded she was consulting her watch, for she went on, "It is nearly ten o'clock. Shall I have Mr. Potter call you?" Mitchell considered before replying. "No. I may have to go out, so I will ring him up. Thank you, Madam; good night." He barely caught her hoarsely echoed "Good night," before hanging up the receiver. Mitchell paused to jot down the Potters' telephone number in his notebook, then, securing his hat and overcoat, made for the street. Only pausing to exchange a hasty greeting with a brother officer, he jumped into the police car. "The Baird house in Georgetown, Allen," he directed, and sat in impatient silence as they whirled through the city streets. He was tired of inaction. Whatever the hour he could not rest until he had interviewed Kitty Baird. Mitchell had gained his promotion to inspector through ability, backed by dogged determination. He had early decided that the mystery of Miss Baird's murder could best be solved through watching Kitty Baird and, as he had expressed it earlier that evening to Coroner Penfield, "wringing the truth from her."