Cape Town – The infighting gripping the City of Cape Town's top tier of officials has heated up even further with Mayor Patricia de Lille's executive director saying he's seeking legal advice as he believes she has defamed him.Craig Kesson issued a statement on Thursday in which he said that claims De Lille made about him in a statement of her own on Wednesday were an attack on his character.Kesson's statement was the second to be released on Thursday which portrayed De Lille unfavourably. Earlier in the day DA federal council chairperson James Selfe labelled De Lille's claim that there were attempts within the party to undermine spatial integration in the city as "nonsense".The claims and counterclaims between De Lille and Kesson stem from a 42-page affidavit by Kesson which became public last Tuesday.In it Kesson made scathing allegations against De Lille.These included that she had planned to publicly discredit a senior city staffer who questioned alleged tender irregularities. Another claim was that De Lille asked that a report into a possible R43m loss regarding another tender be made to "go away".READ: 'Bullying' De Lille wanted alleged tender irregularity report to 'go away' - executive directorOn Wednesday De Lille then issued a statement in response to Kesson's affidavit saying that his "false" disclosures could not be viewed as the actions of a whistleblower but were instead a criminal offence.She said she also believed Kesson leaked information and claims against her to certain politicians which "is suggestive of a political campaign".ALSO READ: It's criminal, not whistleblowing – De Lille hits back at executive director’s claimsOn Thursday Kesson said he had taken note of De Lille's comments although the statement, which he said "contains an ad hominem attack on me", had not been sent to him."This is unsurprising given the treatment whistleblowers receive. I have also noted that the mayor has chosen to use city-funded machinery to issue this statement."Kesson said he felt no malice towards De Lille or any other official.Defamatory"I note the reference in the statement to alleged (unspecified) criminal conduct on my part which has now been widely published by the mayor and which I believe is defamatory of me," he said."I am taking legal advice and reserve my rights."Meanwhile, City of Cape Town urban development MMC Brett Herron said he had also instructed his lawyers "to start proceedings of deformation" against councillors making corruption allegations "frivolously or recklessly or without evidence".Herron is implicated in the overlooking of alleged corruption by a commissioner in his department, Melissa Whitehead. "We must now let the investigation unfold and let the truth come out and then I think you will see that these are not allegations of corruption and in fact this is political nonsense," Herron told News24 at a #ArrestZuma gathering at the Cape Town central train station. "I have absolutely nothing to hide; I am supportive of the (city council's) investigation."#ArrestZuma Responding to corruption allegations within his own department, Brett Heron called the allegations “baseless.” pic.twitter.com/BlIxd6XJNH— James de Villiers (@pejames) November 30, 2017Last Tuesday, the City of Cape Town council held a special confidential meeting and unanimously resolved that the city's audit and performance audit committee be instructed to appoint an independent investigator to probe allegations against Kesson, city manager Achmat Ebrahim and Whitehead.Selfe said on Thursday that in June the federal executive decided to launch an inquiry into "obvious political tensions" within the Cape Town caucus.The inquiry, which has been concluded, involved looking into allegations of wrongdoing, including those of maladministration.READ ALSO: De Lille is talking 'nonsense' - DA federal council chairAn independent investigation into the matter was also launched.The deadline for this probe is December 29. A full report will then be presented to the council.Selfe said the council would meet next Tuesday to decide on the suspensions of the implicated officials.