122. The Court concludes that the Legislative Assembly’s refusal to lift the parliamentary immunity of the then congressman Aércio Pereira de Lima was an arbitrary act, which transformed it into a mechanism that favored his impunity for the murder of Ms. Barbosa de Souza, making illusory the effective access to justice of her next of kin in the instant case. 123. Therefore, the Court considers that the application of parliamentary immunity in the case sub judice violated the right of access to justice of Mrs. M.B.S. and Mr. S.R.S., in relation to the obligations of respect and guarantee and the duty to adopt provisions of domestic law. B.2 The alleged lack of due diligence in the investigation of the other suspects 124. With regard to the alleged lack of due diligence in the investigation of the other suspects, the Court deems it pertinent to recall the nature of the murder of Márcia Barbosa de Souza, since this has consequences for the present analysis, even though the facts related to the homicide are not within the Court’s temporal jurisdiction. In fact, the Court finds it plausible that the homicide of Ms. Barbosa de Souza was committed for gender reasons (supra para. 88) and that, despite the strong indications that Márcia Barbosa de Souza’s violent death was the result of gender-based violence, the State did not conduct any evidentiary procedures to establish this. 125. The Court recalls that when there are specific indications or suspicions of gender-based violence, the authorities’ failure to investigate the possible discriminatory motives behind an act of violence against women may in itself constitute a form of gender discrimination.221 The ineffectiveness of the courts in individual cases of violence against women fosters an environment of impunity that facilitates and promotes the repetition of such acts of violence and sends a message that violence against women can be tolerated and accepted, which encourages its perpetuation and society’s acceptance of the phenomenon, the perception and sensation of insecurity for women, and also their continued lack of confidence in the system for the administration of justice.222 This ineffectiveness or indifference constitutes, in itself, discrimination against women in their access to justice.223 126. It should also be emphasized that due diligence in the investigation of the violent death of a woman also implies the need to investigate from a gender perspective.224 Cf. Case of Véliz Franco et al. v. Guatemala. Preliminary objections, merits, reparations and costs. Judgment of May 19, 2014. Series C No. 277, para. 208, and Case of Vicky Hernández et al. v. Honduras, supra, para. 107. 222 Cf. Case of González et al. (“Cotton Field”) v. Mexico, supra, paras. 388 and 400, and Case of López Soto et al. v. Venezuela. Merits, reparations and costs. Judgment of September 26, 2018. Series C No. 362, para.223 223 Cf. Case of Véliz Franco et al. v. Guatemala, supra, para. 208, and Case of López Soto et al. v. Venezuela, para. 223. 224 According to the Latin American Model Protocol for the investigation of gender-related killings of women (femicide), investigating the killing of a woman from a gender perspective serves to: “[e]xamine the act as a hate crime, […]; address the killing of women not as a circumstantial or coincidental act but as a systematic crime […]; [go] beyond lines of inquiry that are based on individual factors, and which tend to be pathologized to present the aggressors as “crazy,” “out of control,” or “jealous,” or to conceive of these killings as the result of “crimes of passion,” “lovers quarrels” or “sex scandals;” [d]ifferentiate femicides from the deaths of women taking place in other contexts […]; [a]void value judgments about the victim’s prior conduct or behavior and break away from the social and cultural patterns that blame the victim for what happened to her (“she must have done something,” “she was looking for trouble,” “maybe she provoked him”) […]; [b]ring power asymmetries to light, as well as the way in which gender inequalities permeate differences in the roles, norms, practices, and cultural conceptions of men and women [… and] [s]eek legislative alternatives in terms of preventing gender-related killings of women, recognizing that historically women have been discriminated against and excluded from the full and autonomous exercise of their rights.” (Cf. OHCHR and UN Women. Latin American Model Protocol for the investigation of gender-related killings of women, supra, para. 102.) The Latin American Model Protocol for the investigation of gender-related killings of women was drafted in 2014 by the Central America Regional Office of the United Nations High Commissioner for Human Rights (OHCHR), 221 -38-