Police have raided an address in Lincolnshire and one in Greenwich, south London, as part of their investigations into the murder of a soldier in Woolwich.
Metropolitan Police detectives searched the house in Saxilby in connection with the butchering of the man in broad daylight on a southeast London street.
Police are investigating claims that one of the suspects may have links in Lincolnshire. The house is said to belong to the father of named suspect Michael Adebolajo, aged 28.
It is believed Adebolajo had a Muslim name, Mujaahid, which means one who engages in Jihad.
A Lincolnshire Police spokesman confirmed the raid is "in connection with the ongoing investigation into the murder of a man in Woolwich."
The Met added: "We can confirm that the MPS executed a search warrant at an address in Lincolnshire. This is connected to the ongoing investigation into the murder of a man in Woolwich."
According to ITV, police and forensics are also searching a flat in Greenwich thought to be linked to one of the men.
Two men have been arrested in connection with the incident which police are treating as a terrorist attack.
The men, who are both believed to be British but of Nigerian background, remained at the scene for around 20 minutes until the police arrived.
The men were shot and apprehended by armed officers. The extents of their injuries are not known.
Following the killing, a video emerged of Adebolajo holding a meat cleaver in his bloodied hands, telling the person filming :"We swear by almighty Allah we will never stop fighting you".
Adebolajo added: "The reason we have killed this man today is because Muslims are dying daily by British soldiers.
"And this British soldier is one. It is an eye for an eye and a tooth for a tooth. By Allah, we swear by the almighty Allah we will never stop fighting until you leave us alone
"I apologise that women had to witness this today but in our lands women have to see the same.
"You people will never be safe. Remove your governments, they don't care about you."
Just a normal guy
According to reports, Adebolajo converted to Islam in 2003.
Anjem Choudary, a former leader of the banned Islamist group Al Muhajiroun, told the Independent he met the suspect in the video two years ago.
He said: "He was just a completely normal guy. He was interested in Islam, in memorising the Koran. He disappeared about two years ago. I don't know what influences he has been under since then."
Asst Comm Simon Byrne, of the Met Police, said on the Woolwich murder investigation. "Today our shock at what happened on the streets of our city remains. The investigation into the shocking murder of a serving soldier yesterday is ongoing, and is of course a major investigation for us.
"It is only right that the ongoing investigations are allowed to take place, and they must take as long as is needed without anyone pre-empting what they may conclude.
"I would ask for Londoners help and support for us to continue. Please remain calm. London is at its best when we all come together and now is the time to do that."