The service was held at a cinema in Umlazi township, south of Durban, after Mxenge was murdered outside her Umlazi home. Her husband, Griffiths Mxenge, was murdered on November 19, 1981.
Five former security policemen, including former Vlakplaas commander Dirk Coetzee, have been charged with his murder.
African National Congress member and former United Democratic Front activist David Sponono Gasa told the commission at the Durban Christian Centre on Wednesday that men armed with spears and knobkerries attacked mourners outside the cinema, killing 15 people.
Gasa said he made a statement to the press in which he blamed Umlazi IFP leader Wellington Sabelo for the attack. Sabelo has since died.
Gasa said after his statement to the press he became a target for Inkatha. His house was gutted four days after issuing the statement.
He said the attack was prompted by inciting remarks made by the IFP general-secretary at the time, Oscar Dhlomo, who said on state television Gasa's remarks to the press would "irritate" Inkatha.
"Oscar Dhlomo (also said) I should be aware that my neighbours were Inkatha members and they would be angered by my press statement. Four days later my house was burnt down," Gasa said.
He said his wife's health had deteriorated because of the attack and she died six months later.
Gasa called for Dhlomo to be held accountable for his wife's death.
Another witness, Josiah Dlamini, testified that he had given permission as manager of the cinema for the memorial service to be held there and afterwards was also targeted, allegedly by Inkatha members.
Dlamini said he was eventually evicted from the cinema and his equipment was confiscated by the KwaZulu Finance Corporation.
Addressing the commission on the murder of his son, Jacob, in Lindelani near Durban, allegedly by Inkatha, Dlamini said he had approached IFP leader Mangosuthu Buthelezi to report the matter to him.
He relayed the message to Buthelezi via Buthelezi's security guards at a meeting in Maphumulo on the north coast in the late 1980s.
"Chief Buthelezi came to my car and when I attempted to open the rear door for him, he contemptuously stopped me, saying I must remain in the driver's seat."
When he tried to explain that his son had allegedly been murdered by Inkatha members, Buthelezi had remonstrated with him.
He said he was assaulted by two men accompanying Buthelezi.
Dlamini said another of his sons was murdered, allegedly by notorious Lindelani IFP leader Thomas Shabalala. Shabalala was recently prevented from holding office in the IFP for two years for bringing the party into disrepute.
Earlier during the hearing, Umlazi resident Sandile Thusi told the commission he had been harassed and detained by members of the police special branch.
Thusi claimed his family was verbally abused and his pregnant sister was assaulted by police in September 1985.
He said his brother had died after an attack on his home on October 23, 1985.
Thusi claimed police arrived shortly after the attack, but refused to assist the wounded because they were "UDF dogs". His brother died three days later.
Thusi said he now suffered from "withdrawal syndrome" as a result of continued harassment by police at that time. He had been detained several times.
"I was kept in solitary confinement and was refused visitors. I was poisoned with liquid paraffin after each and every meal," Thusi told the commission.
His statement was one of six on Wednesday accusing police of complicity in violence and of failing to bring perpetrators of crime and violence to book.
Theresa Khumalo said her son, Mfanafuthi, was shot and wounded, allegedly by KwaZulu policeman Sphiwe Mvuyane from Umlazi police station, in the early 90s. Mvuyane has since died.
Thamsanqa Templeton Ndimande of KwaMashu, north of Durban, said her son, Sibonelo Ngeke, was shot and wounded by a KwaZulu policeman during Shaka Day celebrations in 1992.
She did not report the incident at the time, believing police would not act against the policeman.
Nomakesi Victoria Mabaso of Umlazi told the commission her son, Xolani Sifiso Poyo, was shot dead by Amanzimtoti police on Sharpeville Day in 1992.
On Thursday victims of the 1987 KwaMakutha massacre are due to testify about 13 people, mostly women and children, who were shot dead in a home in KwaMakutha on January 21.
Former Defence Force Minister Magnus Malan and 16 others are standing trial on charges arising from the massacre.