While these facts were being brought to light in one direction, information of the greatest value had been secured in another, and which confirmed, almost beyond question, the general belief that Dr. Cronin had been murdered in the Carlson cottage. It came from William Mertes, a milk dealer of reputation and good standing in the community, and who lived on Woodside avenue in Lake View. On the night of May 4th, somewhere between 8:30 and 9 o'clock, Mertes left his house to visit the grocery at the corner of Ashland avenue and Otto street, which was only a short block south of the cottage. He walked east on Addison avenue to Ashland, and then turned south on the east sidewalk. As he neared the Carlson cottage at Roscoe street a buggy containing two men rolled up to the edge of the ditch. One of the men, whom Mertes described as a tall and apparently athletic man, sprang from the buggy and ran up the front stairs of the cottage, the door of which was thrown open before he even knocked for admission. Scarcely had the door closed again when the sound of loud and angry voices within the cottage startled the milk dealer. He looked searchingly at the man in the buggy, wondering what had brought him to that lonely neighborhood at such an hour of the night, but the stranger's face was shrouded by the brim of a soft hat, and Mertes was unable to tell whether he was stout or slender, or fair or dark. The fellow whipped his horse into a gallop, drove to Addison avenue and then turned in the direction of the lake. Mertes thought at the time that a fight was in progress, but as he heard only words he paid but little attention. [Illustration: MILKMAN MERTES.] "Were there any lights in the house?" he was asked. "Yes, there was a light, a small one, in the front room of the first floor. I could see it through the blinds." "Could you distinguish the loud words you heard?" "No, I could not. I tried to, but as they were spoken in the house they did not reach me." "Did you hear any sounds that would indicate that a scuffle was in progress?" "No; I listened for them because I thought there was a fight." "Did you hear any loud words before the man from the buggy entered?" "No, I didn't; but I was a long way from the house then." "Did you see the man's face?" "He ran up the stairs in too much of a hurry for me to get a glimpse of him. He appeared to be in a terrible hurry." "Did he speak to the man in the buggy before the latter drove away?" "I think not." "Do you remember whether he knocked for admission?" "I don't believe he did. He had scarcely reached the landing when I heard the bolt of the door fly back and then it opened, and he went in." "And you heard the loud words directly afterward?" "Yes; just as soon as the door closed." "How was the man dressed?" "My impression is that he had on a long overcoat, which was of a brown color, but I wouldn't be sure of it." "Did he have a box or parcel in his hand?"