“When Doctor Walker went away to California with the Armstrong family, there was talk in the town that when he came back he would be married to Miss Armstrong, and we all expected it.  First thing I knew, I got a letter from him, in the west.  He seemed to be excited, and he said Miss Armstrong had taken a sudden notion to go home and he sent me some money.  I was to watch for her, to see if she went to Sunnyside, and wherever she was, not to lose sight of her until he got home.  I traced her to the lodge, and I guess I scared you on the drive one night, Miss Innes.”

“And Rosie!” I ejaculated.

Riggs grinned sheepishly.

“I only wanted to make sure Miss Louise was there.  Rosie started to run, and I tried to stop her and tell her some sort of a story to account for my being there.  But she wouldn’t wait.”

“And the broken china—­in the basket?”

“Well, broken china’s death to rubber tires,” he said.  “I hadn’t any complaint against you people here, and the Dragon Fly was a good car.”

So Rosie’s highwayman was explained.

“Well, I telegraphed the doctor where Miss Louise was and I kept an eye on her.  Just a day or so before they came home with the body, I got another letter, telling me to watch for a woman who had been pitted with smallpox.  Her name was Carrington, and the doctor made things pretty strong.  If I found any such woman loafing around, I was not to lose sight of her for a minute until the doctor got back.

“Well, I would have had my hands full, but the other woman didn’t show up for a good while, and when she did the doctor was home.”

“Riggs,” I asked suddenly, “did you get into this house a day or two after I took it, at night?”

“I did not, Miss Innes.  I have never been in the house before.  Well, the Carrington woman didn’t show up until the night Mr. Halsey disappeared.  She came to the office late, and the doctor was out.  She waited around, walking the floor and working herself into a passion.  When the doctor didn’t come back, she was in an awful way.  She wanted me to hunt him, and when he didn’t appear, she called him names; said he couldn’t fool her.  There was murder being done, and she would see him swing for it.

“She struck me as being an ugly customer, and when she left, about eleven o’clock, and went across to the Armstrong place, I was not far behind her.  She walked all around the house first, looking up at the windows.  Then she rang the bell, and the minute the door was opened she was through it, and into the hall.”

“How long did she stay?”

“That’s the queer part of it,” Riggs said eagerly.  “She didn’t come out that night at all.  I went to bed at daylight, and that was the last I heard of her until the next day, when I saw her on a truck at the station, covered with a sheet.  She’d been struck by the express and you would hardly have known her—­dead, of course.  I think she stayed all night in the Armstrong house, and the agent said she was crossing the track to take the up-train to town when the express struck her.”