[6][7] The pogrom was premeditated,[8][9][10][11][note 1] and was finally triggered by a deadly ambush on a Sri Lankan Army patrol by the Liberation Tigers of Tamil Eelam (LTTE) on 23 July 1983, which killed 13 soldiers.

[24] During the period of British colonial rule, Sri Lankan Tamils from the Jaffna peninsula benefited greatly from educational facilities established by American missionaries.

[34] In the 1970s, Tamil militant groups began taking form with notable incidents such as the assassination of Alfred Duraiappah, the Mayor of Jaffna, in 1975 and the killing of Inspector Bastianpillai and his police team in 1978.

There were many murders, disappearances, and cases of torture attributed to the Sri Lankan security forces, and several killings of policemen by Tamil militant groups.

[48][49][50] Around midnight, following the news of the attack, the Army began to move all their Tamil officers from Colombo and Panagoda to a camp in Ampara, in an isolated area not affected by the subsequent riots.

[46] Preparations were made for the funeral, including putting the riot squad at the police station in nearby Borella on standby; but by 5 pm the bodies hadn't arrived in Colombo.

A large crowd, including around 3,000 people from the Wanathamulla slum, started gathering at the cemetery, angered by news of the ambush, which was magnified by wild rumour.

[57] Just hours after the news of the ambush reached Colombo, small gangs were on the streets with typewritten lists of the names and addresses of Tamil owned properties, suggesting prior planning and organisation.

"[59]By 10 am, the rioting had spread to the slums of Canal Bank, Grandpass, Hattewatte, Kirilapone, Kotahena, Maradana, Modara, Mutwal, Narahenpita, Slave Island, and Wanathamulla.

[64] The possession of electoral lists by the mobs, which enabled them to identify Tamil homes and property, implied prior organization and cooperation by elements of the government.

[64] Indian-owned factories such as Kundanmals, Oxford, and Bakson Garments were not attacked, giving credence to the suggestion that the mob was deliberately going after Sri Lankan Tamil targets.

[76] The police managed to get control of the situation, but an hour later a mob armed with petrol cans and Molotov cocktails started attacking Tamil shops on Castle, Colombo, King's, and Trincomalee streets.

[76] In Trincomalee, false rumours started spreading that the LTTE had captured Jaffna, that the Karainagar Naval Base had been destroyed, and that the Naga Vihare had been desecrated.

[78] Badulla, the largest city in neighbouring Uva Province, had so far been peaceful; but around 10:30 a.m. on 27 July, a Tamil-owned motorcycle was set on fire in front of the clock tower.

[78] The home of one Mr Ramanathan, an Indian Tamil camphor dealer in Badulla was attacked by the Sri Lanka Army with the support of UNP MP Vincent Dias' three brothers and a Sinhalese mob.

[81] The mob then left the city in vans and buses that they had stolen and headed for Bandarawela, Hali-Ela, and Welimada, where they continued to set properties on fire.

That night the government banned three left-wing political parties—the Communist Party of Sri Lanka, Janatha Vimukthi Peramuna, and the Nava Sama Samaja Party—blaming them for inciting the riots.

[105] In an interview with the Daily Telegraph on 11 July 1983, about two weeks prior to the riots, Jayewardene admitted to a reporter: I am not worried about the opinion of the Jaffna (Tamil) people now.

[110][111][112][113] On Friday 29th July, the Prime Minister Ranasinghe Premadasa in a nationwide broadcast blamed the Tamils for the week long mayhem that occurred during the pogrom.

[114] Another minister Ranil Wickremasinghe stated that the burning of factories and other premises belonging to Tamils during the pogrom was "nothing compared to the tragedy imposed on the Sinhala entrepreneur by the Bandaranaikes since 1956."

[117] On August 4th, Sarath Muttetuwegama questioned the government in parliament on why it did not announce an immediate curfew on the morning of 25th July, when violence had begun the previous evening.

The state apparatus was used..."[118] Following the riots, Prime Minister Premadasa formed a committee to organise shelter for, and feeding of, an estimated 20,000 homeless Tamils in Colombo.

[80] A few weeks after the pogrom, in September 1983, Gamini Dissanayake, a cabinet minister, gave this message to Tamil estate workers in reference to the violence: Who attacked you?

[120] The Tamil Guardian lists more eyewitness testimonies from various sources:[121] London's The Daily Telegraph (26 July) wrote: Motorists were dragged from their cars to be stoned and beaten with sticks.

Mobs of Sinhala youth rampaged through the streets, ransacking homes, shops and offices, looting them and setting them ablaze, as they sought out members of the Tamil ethnic minority.

While all this was going on, a line of Buddhist monks appeared, arms flailing, their voices raised in a delirium of exhortation, summoning the Sinhalese to put all Tamils to death.The London Daily Express (29 July) wrote: Mrs Eli Skarstein, back home in Stavanger, Norway, told how she and her 15 year old daughter, Kristen witnessed one massacre.

The Hindu reported that German holiday makers from Düsseldorf witnessed "hundreds of Tamils being murdered" and stated that their hotel waiter proudly told them "we have killed several of them.

"[122][123] Francis Wheelan of the New Statesman referring to the aftermath of the violence stated: A few minutes after arriving in Sri Lanka last month, I was sitting on the pavement outside Katunayake airport, watching the birds and the dragonflies.

'[124][125]Paul Sieghart of the International Commission of Jurists stated in Sri Lanka: A Mounting Tragedy of Errors, two months after the riots, that: "Clearly this (July 1983 attack) was no spontaneous upsurge of communal hatred among the Sinhala people – nor was it as has been suggested in some quarters, a popular response to the killing of 13 soldiers in an ambush the previous day by Tamil Tigers, which was not even reported in the newspapers until the riots began.

[15] N. Shanmugathasan, the general secretary of the Ceylon Communist Party stated that Tamil patients in hospitals were also attacked and killed, with some having their throats slit whilst lying in bed.