The day after Paul Kevin Curtis was apprehended on charges of sending ricin-laced envelopes to Capitol Hill and the White House, court records show that the lead-up to the arrest was led largely by the Capitol Police.

“[They] did the brunt of the front end work on this,” Senate Sergeant at Arms Terrance Gainer said in a conversation with CQ Roll Call.

“Obviously, we were in partnership with the [FBI] and other agencies, but our folks did an outstanding job during the course of the initial, and the main parts of, the investigations to put all the pieces together,” Capitol Police Chief Kim Dine told CQ Roll Call in a separate interview.

On Tuesday, according to the sworn affidavit from FBI Special Agent Brandon M. Grant, the Senate’s off-site mail-handling facility in Landover, Md., intercepted a letter addressed to Sen. Roger Wicker, R-Miss.

Postmarked on April 8 from Memphis, Tenn., and bearing no return address, the envelope contained a suspicious substance that ultimately tested positive for poisonous ricin, and a note, which was formatted like a poem with line breaks and erratic punctuation. Preliminary tests all pointed to the substance being ricin, and the FBI confirmed it Thursday.

“No one wanted to listen to me before,” the letter read, according to Grant’s statement. “There are still ‘Missing Pieces’/Maybe I have your attention now/Even if that means someone must die./This must stop./To see a wrong and not expose it,/is to become a silent partner to its continuance/I am KC and I approve this message.”

The Capitol Police took the key first step: It asked Wicker’s office whether it had ever had any correspondences with a constituent who had the initials “KC.”

It turned out, the Washington office had heard multiple times from someone named Paul Kevin Curtis, who in each correspondence signed off with the line “This is KEVIN CURTIS and I approve this message.”

On Sept. 24, 2010, Grant continued, Curtis posted on his blog that he was writing a novel about black-market body parts that he called “Missing Pieces.” It was later revealed that fellow Mississippi Republican Rep. Alan Nunnelee had also received an email from Curtis that referred to the novel by its title.

It all went back, of course, to the line in his poem to Wicker about “Missing Pieces.”

Then, in another connection, officers found that on April 12, Curtis posted on his Facebook page the phrase, “To see a wrong and not expose it, is to become a silent partner in its continuance,” invoking a line in the note included in the ricin-laced envelope.

An identical letter that also tested positive for ricin was subsequently intercepted before reaching President Barack Obama on Wednesday; Justice Court Judge Sadie Holland in Lee County, Miss., got one as well.

Meanwhile, inspectors with the U.S. Postal Service confirmed that correspondence “in most, if not all, of the northern counties in the State of Mississippi, including Lee County, will bear a Memphis, Tennessee, postmark.”

It meant law enforcement officials had found their guy. Gainer even said Capitol Police officers were on their way to Mississippi on Wednesday to apprehend Curtis at his home in Corinth when federal agents, working in partnership with the Capitol Police, got to him first.

Dine, still new to the Capitol Police department after being sworn in as chief at the end of December, expressed pride and appreciation for his officers. He also called the events of the past 48 hours a perfect case study in what makes the force so unique.

“A lot of people don’t understand the many facets of the agency,” Dine said. “We’re a little bit like all these other agencies. We do dignitary protections, so kind of like the Secret Service, but we also do investigations like the FBI does and intelligence and obviously security pieces like Homeland Security  . . .  We’re a lot like multiple agencies all rolled into one.”

But while Wednesday night’s arrest would suggest the case is closed, Dine said the investigation is far from over — it’s yet to be determined how Curtis came into possession of ricin.

“There’s a whole lot more work to do,” Dine said, and it will take “a lot of teamwork.”

Daniel Newhauser contributed to this report