On Wednesday night, Lennon was the subject of an assault at Tynecastle and a package containing ammunition was found at Celtic Park yesterday.
Two men were later arrested in connection with an investigation into parcel bombs sent to Lennon and to two high-profile supporters of the club, Strathclyde Police said last night.
The men, aged 41 and 43, were detained yesterday morning after officers raided a number of properties in Kilwinning, Ayrshire.
Police later said they had been arrested and detained under the Explosive Substances Act (1883). The two are expected to appear in court today.
Police launched a major investigation after two bombs were sent to Lennon and one each to lawyer Paul McBride and former MSP Trish Godman. A fifth suspect package, addressed to the offices of Cairde Na H’Eireann (Friends of Ireland) in Glasgow, was also intercepted by officers last month.
Police were also called to Celtic Park yesterday after a suspect package which was believed to have contained a bullet and addressed to Lennon was found.
Yesterday a man appeared in court charged in connection with the Tynecastle incident, which took place after Gary Hooper scored the second goal in Celtic’s 3-0 SPL win.
John Wilson, 26, of Edinburgh, was charged with breach of the peace aggravated by religious prejudice and assault aggravated by religious prejudice. He made no plea and was remanded in custody.
Celtic came out fighting yesterday with Lawwell condemning the assault on Lennon. Lawwell said the Tynecastle incident “brings shame on Scottish football and again highlights the fact that Scottish society must address fundamental and serious issues which lead to outrages of this kind”.
Lawwell called for Lennon to be given the same licence as other managers to carry out their jobs.
“It is intolerable that any football club, or individual, going about their lawful business in the name of sport should be subjected to this ongoing campaign of hatred and intimidation,” he said.
“This is Scotland’s shame and it is high time Scotland addressed it.
“Since moving here a decade ago, Neil Lennon has had to endure prejudice and violence both as a player and manager, having suffered no such problems elsewhere.
“In doing so, he has displayed a strength of character and resilience which deserve respect from all who oppose the campaign of intimidation against him.
“He is a man who is proud to be the Celtic manager and is someone who simply wants to be able to carry out his role in the same way as every other football manager. Clearly, Neil will continue to receive every support and protection from Celtic FC.”
Lawwell also referred to an incident which led to seven people appearing in court charged with possessing an imitation firearm.
Lawwell said: “Apart from last night’s events, this week alone we have seen seven people arrested at our training ground following an alleged firearms incident and I can also confirm that this morning another package arrived at Celtic Park which appears to contain ammunition.
“This has been removed and taken by police for further forensic tests.
“We are the only club to be the subject of such vile, sustained and relentless attacks. All right-minded people will surely condemn these actions but, as a society, we must also address the underlying factors that lead to such behaviour.”
Lennon was said to have been “shaken’’ by events at Tynecastle. But, despite off-field concerns, Lennon was focused on his team’s success.
Two goals from Gary Hooper and a Kris Commons strike kept alive Celtic’s SPL title hopes.
Celtic now need a better result against Motherwell on Sunday than Rangers achieve against Kilmarnock.
The Celtic boss wrote on Twitter: “Don’t let what happened to me take the shine off a wonderful team performance... I don’t walk alone.”
Lennon’s agent, Martin Reilly, later insisted his client would not quit.
Reilly said: “Neil is shaken about the whole thing, but he won’t be driven out of Scotland. Neil is concentrating on trying to win the SPL and the team has a Scottish Cup final to contest. At the end of the season I will sit down with Neil and if there are things that he’s unhappy about then I will try and fix them. He won’t throw in the towel.”
However Lennon’s former team-mate Paul Hartley fears the Celtic boss will be forced to walk away. Hartley said: “You have to fear for Neil Lennon now. You have to fear what else is going to happen.
“I think it’s an utter disgrace. Neil’s been under so much pressure over the last couple of months. “I think Neil will sit down in the summer and think ‘is this worth it?”