sentences:  The murder of the worker Jerzy Grabczyński by Russian Cossack cavalry at the Grohmana is mentioned as one of the sparks of the insurrection.On 18 June 1905, Russian police opened fire on one of the many workers' demonstrations in Łódź, killing approximately ten workers, whose funerals, attended by over 50,000–70,000 people, escalated into major demonstrations on 20 and 21 June.The funeral on 21 June was met by Cossack cavalry again; the crowd threw stones, and the Russian cavalry returned fire, killing 25 people and wounding hundreds.