The lawyer is worried about Nnamdi Kanu's wellbeing, especially since the SSS failed to produce the IPOB leader for trial.
One of the lawyers to Nnamdi Kanu said they have been denied access to the IPOB leader.
Mr Kanu, who is standing trial for treason, is detained by Nigeria's secret police, the SSS, in Abuja under a court order.
His lawyer, Aloy Ejimakor, said the SSS, on Thursday, prevented him and two other lawyers from seeing Mr Kanu, despite a court order which permits them to visit him on Mondays and Thursdays.
He said when he and the other lawyers visited the SSS facility, they were surprised that the officials could ask them to go put their request to see the IPOB leader in writing even when the officials were familiar with their previous visits.
"I said let me write the thing on a scrap of paper, they said it should be on a letterhead and should be addressed to the DG of SSS.
"So we went back to our satellite office and prepared such a letter and brought it back. They took the letter from us. We were there around 3:30p.m., so there was still an hour, thirty minutes window for us to see Kanu.
"They asked us to wait in the waiting area. A few minutes later they came and told us that they had taken the letter inside and that we should go and wait for confirmation, clearance, and invitation," Mr Ejimakor said.
The lawyers eventually left without seeing Mr Kanu.
Mr Ejimakor said he was worried about Mr Kanu's wellbeing, especially since the SSS failed to produce the IPOB leader for his scheduled trial at the Federal High Court in Abuja, July 26.
"We are very concerned, the last time I saw him was 12 days ago," he told PREMIUM TIMES, Thursday.
"This Saturday (July 31) will make it two weeks since I saw him with my eyes, and you know access to him is only by his lawyers.
"That means in the past 12 days no one has set eyes on him. I am concerned as much as the multitude of people are concerned about his wellbeing," he said.
"And it is not as if we are going there to see him for fun, we go there to see him physically, better prepared for his defence and to brief him on what we are doing and also to ask him questions about his wellbeing, it is the duty of every lawyer to any criminal suspect in detention.
"I think (the) government has an obligation to make that happen. So this thing they are doing is interfering with his constitutional rights and is fueling legitimate speculations and concerns about his wellbeing."
Since the courts in Nigeria are on vacation, Mr Kanu's lawyers are thinking of approaching a vacation judge to make the order compelling for the SSS to allow access to the IPOB leader.
"I am very sad," Mr Ejimakor said.
The spokesperson for the SSS, Peter Afunanya, did not respond to calls and a text message seeking comment from him.