Clark said that homicide detectives were on their way to catch a plane to Montgomery to bring McFarland back to Philadelphia.
"He will be arrested and charged right now with a couple of robberies," Clark said. "We will send everything over to the District Attorney's Office with hopes he will be charged with murder."
Clark said that cops had been in touch with McFarland's family in Philadelphia and had been communicating with his mother. McFarland also has family in the Montgomery, Ala., area, he said.
Police and U.S. Marshals on Wednesday captured the first suspect, Rafael Jones, 23, of North Philly, inside a Southwest Philadelphia public-housing complex. Jones was charged with murder and related offenses on Friday.
Mayor Nutter said Sunday of the two alleged killers: "Both of them should rot in jail for the rest of their lives and rot in hell after that."
Police say that Jones and McFarland were the two thugs who stalked Walker, 40, a 19-year police veteran, on Cecil B. Moore Avenue near 19th Street, in North Philly, shortly before 6 a.m. Aug. 18 as the off-duty officer, dressed in shorts and carrying a backpack, walked toward a bus stop. Walker had just finished his overnight shift at the 22nd District, at 17th Street and Montgomery Avenue.
On Cecil B. Moore, near 20th, police say, the two men confronted Walker and announced a robbery, and Jones shot and killed Walker.
Before Sunday's viewing, police lined up on Lehigh Avenue near 31st Street to begin the procession to escort Walker's body to the church.
Officers from the 22nd District, dressed in dark blue, carried Walker's body in a flag-draped, silver-colored casket from the Cordoza Jacks Funeral Home hearse and placed it inside a carriage, led by two white horses.
As Walker's family lined up for the procession, Nutter put an arm around Walker's mother and escorted her to the front-passenger seat of the hearse.
Nutter and Ramsey led the procession on Lehigh Avenue toward the church. Drummers with the Philadelphia Police & Fire Pipes & Drums played the solemn beats of a funeral dirge, the familiar Chopin Funeral March.
The solemnities continue Monday with a second viewing at the church from 7 to 10 a.m., followed by a funeral service. Walker will be buried after the service at Fernwood Cemetery, in Lansdowne, Delaware County.
Contact Julie Shaw at 215-854-2592 or shawj@phillynews.com. Follow her on Twitter @julieshawphilly.