The decline of institutional trust in official media in Iran has paved the way for the emergence of new forms of persuasion in citizen media. This study aims to uncover the persuasive mechanisms embedded in the "Vahid Online" model, as one of the most influential Persian-language citizen-journalists during the Iran-Israel war period (March 2025). Using a Grounded Theory methodology and analyzing two independent data sources. a thematic analysis of high-traffic tweets (45 tweets) and a quantitative-structural report on the performance of the Telegram channel (2,173 posts) the study identifies eight persuasive mechanisms: controlled imperfection, anti-institutional framing, the curious citizen identity, habitual dependency, hidden gatekeeping, speed over certainty, designed parasocial intimacy, and identity-based brevity. The findings suggest that, contrary to classical persuasion theories emphasizing "source credibility" and "argument quality," the Vahid Online model relies on performative weakness, speed, pseudo-participation, and engineered intimacy. Under conditions of institutional trust decline, these mechanisms produce a form of "impoverished credibility" that replaces eroded institutional credibility. By offering a grounded theory of persuasion in a crisis media ecosystem, this study provides a generalizable framework for analyzing citizen media in societies experiencing institutional trust decline.