In total, 12 people have been arrested as part of the investigation, police said.
Another man, 58, also arrested in Birmingham, remains in police custody after a series of raids across the country.
Four wreaths were laid on the pitch by Metropolitan Police Acting Commissioner Craig Mackey, London Mayor Sadiq Khan, FA chairman Greg Clarke and Culture Secretary Karen Bradley.
Police investigating the attack on parliament made a new arrest yesterday as officials set their sights on accessing WhatsApp, the messaging service that was used by the killer.
Cochran was struck and killed by the terrorist's speeding SUV while crossing the Westminster Bridge. We're trying to focus on giving her healing energy. She is so grateful and overwhelmed with you generosity and out pouring of love.
He said she is still recovering from a broken leg and rib.
"She's a fighter", Burton said.
She is understood to have been 43 and married with two daughters.
A minute's silence was held in the Galician municipality of Betanzos, where Mrs Frade's family originates and where she spent her summers.
Among the deceased is Utah resident Kurt Cochran.
"We know that Kurt wouldn't bear ill feelings towards anyone and we can draw strength as a family from that", Payne said. He and his wife ran a recording studio out of their home in West Bountiful, a small town north of the city.
Neighbours paid tribute to the 75-year-old as "a lovely man" and said he had been "as fit as a fiddle" despite his age. "He was always around when there were music things going on". In one post, he was smiling and holding a German beer under the caption, "After a long day of sightseeing".
'It has been a tender experience for our family to be together with Melissa here.
"(It) just does not feel real", Layton said.
Family spokesman Clint Payne told reporters Tuesday that Cochran's wife, Melissa, is steadily improving.
Steve Hatch, 46, said he just talked with Kurt Cochran online about how much fun the couple was having on the trip.
He said he still can't believe that the terror attack hit so close to home.
Rhodes was from Streatham, in south London.
"I am so deeply shocked, saddened and numbed by the actions my son has taken that have killed and injured innocent people in Westminster".
They are a mix of nationalities including three French high school students, all boys, who were visiting London from Brittany.
Saturday, authorities released a timeline of the attack, saying it lasted 82 seconds and started at 2:40 p.m. local time when the auto Masood was driving over Westminster Bridge first mounted the sidewalk.