Within hours of the bombing,
forensic investigators had recovered fragments of a timing device at the crime scene—confirming suspicions the explosion had been caused by a
time bomb. Furthermore,
eyewitnesses confirmed the bicycle had been parked at the location, directly behind a car, for between three-quarters of an hour and an hour before detonation. Although the vast majority of the bicycle frame was destroyed in the explosion, the serial number was still visible upon the remnants of the rear of the frame, enabling investigators to trace the bicycle to the Halfords on Smithford Street. The owner confirmed he had sold the bike to two Irishmen—one of whom gave his name as Norman—on 22 August, and that the bicycle had been collected from his premises the day before the bombing. Furthermore, the Irishman who had collected the bicycle and paid the outstanding balance was not the same individual who had paid the £5 deposit. The name and address given by these individuals proved to be false, although the seller provided police with detailed descriptions of both men.
Arrests Barnes was arrested at his lodgings in Westbourne Terrace, London, at 20:50 on the evening of the bombing. His arrest resulted from an independent
Special Branch police raid upon a flat in
Leinster Gardens,
West London, in relation to numerous local thefts of bicycles by the tenants of the property which investigators suspected of being used in the transportation of explosives around the city by the IRA. A search of the property revealed a large quantity of explosives stowed in hat boxes and a timing device. Questioning of the four Irishmen arrested revealed the explosives were brought to the property by one Peter Barnes. One of these individuals provided police with his address, and Barnes was arrested as he returned to the property from Coventry. A search of Barnes's address uncovered ample
incriminating evidence with regards to the Coventry bombing, including a suitcase bearing traces of potassium chlorate, and an unposted letter to an acquaintance in Ireland in which Barnes detailed his involvement in and expectation of a forthcoming "spectacular" bombing and concluding with "I am coming back from Coventry tonight 11:30, so by the time you get this, the [newspapers] should have some news." When asked if he had been to Coventry earlier that day, Barnes replied he had, before adding, "Coincidences can happen, can't they?" He was promptly arrested and detained at
Canon Row Police Station, but refused to name the man he had provided the explosives to in Coventry. On 28 August, the Coventry City Police, along with members of Special Branch, conducted a thorough search of 25 Clara Street. This search also uncovered a suitcase bearing traces of potassium chlorate, plus tools and equipment sufficient for the purpose of constructing bombs and
incendiary devices such as
pincers,
soldering material, and insulating tape. Also recovered were pieces of paper torn from a four-and-a-half
volt dry cell battery and a new and untarnished brass setting device used to set the hands of an alarm clock. This device did not fit any clock in the house. All occupants of the property were arrested under the
Explosive Substances Act 1883. Initially released pending deportation, those arrested at Clara Street were re-arrested on 2 September.
Written statements The following day, both Brigid O'Hara and Mary Hewitt provided written statements in which they admitted several "strange men" had visited McCormick at their house in recent weeks, often bringing suitcases and substances they had suspected were explosives. Neither had known of McCormick's IRA affiliations at the time he had initially lodged with them, although his connections and activity soon became apparent to both. Furthermore, McCormick had always spoken with the men who visited him behind closed doors so that neither woman could hear details of their conversations. Hewitt added that, beginning in mid-August, she had observed McCormick frequently take "white powder" out of a suitcase which he then made "into parcels"; he had continued this practice until the suitcase was empty. He had initially stowed this suitcase in the
scullery before placing the suitcase in the family coal shed once it was empty. In addition, shortly after midday on 25 August, she had observed McCormick and a man she did not know the name of working with tools on a wooden box in her own bedroom. Both women remained adamant they had been fearful of reprisals from not just McCormick but also Joseph Hewitt who, although not a member of the IRA, was sympathetic to their cause. They had therefore chosen to remain silent about these activities. When shown a photograph of Barnes, both women subsequently identified him as having visited their home for the first time on 21 August—apparently to acquaint himself with McCormick and discuss the transportation of the explosives. O'Hara further admitted McCormick had asked her to purchase a suitcase for Barnes during this visit. This suitcase was the one recovered from Barnes's property; the receipt for this purchase was found in the possession of Barnes's fiancée. ==Trial==