“They may have walked in and walked out, and decided: This was easy and we can do it again,” Dunn said.

Townsend has not been charged with participating in the murders, Dunn said. But the sheriff would not rule out the possibility that charges could be filed against others as the investigation proceeds.

Anonymous tips

Dunn said an anonymous tip received on the Sheriff’s Department’s tip line in the latter part of December first gave lead Detective Kevin Mitchell a name and a direction in the case that ultimately proved valid.

“It kind of led to a dead end at one point when a guy lawyered up,” Dunn said.

But a second anonymous tip in May put Mitchell and other investigators back on the same track, and led to the arrests, he said. He declined to identify the man who sought an attorney.

Affidavits allege that Laurin has admitted his and Winans’ involvement in the slayings. There is no indication of any confession on the part of Winans.

The sheriff indicated that the murder weapon has yet to be recovered. He said it still might be located, but the length of time that has passed since the slayings may make that difficult. Dunn said there are detectives still working leads, particularly in the Springfield area. The sheriff declined to say if there was any DNA evidence in the case.

Mitchell and the sheriff credited the Missouri State Highway Patrol, Springfield police and the Greene County Sheriff’s Department with assistance in the investigation.

Private agency

The Globe was contacted by telephone Wednesday before the news conference by a man who identified himself as the executive security consultant for a St. Louis private firm, PDI Investigations. Mike Barbieri said the firm assisted the Sheriff’s Department in solving the murders.

Barbieri said the firm was hired by two cousins in the Sheldon family to look into the murders. Barbieri said investigators developed informants in the area in recent weeks whose information ultimately led to the arrests.

Barbieri correctly identified the two men arrested in the murders before the release of their names by the Sheriff’s Department or the appearance of the charges against them on any court records available on the Internet. He said the firm was in possession of video of Laurin’s arrest Tuesday.

Asked about the matter after the news conference, the sheriff would neither confirm nor deny the private agency’s involvement in the case. He referred all questions along such lines to the prosecutor’s office. Prosecutor Dean Dankelson, who appeared at the news conference to answer reporters’ questions, left at its conclusion and could not be reached for further comment on the matter.

Dunn acknowledged at the news conference that the Sheriff’s Department was under considerable pressure to solve the Sheldon murders, including the expectations of the couple’s family.