MTA officials this week blamed a recent series of subway meltdowns on a copper thief who ripped out wiring in the Bronx.

Transit officials during a meeting on Wednesday said the vandal, identified by the NYPD as 55-year-old Efrain Velez, singlehandedly upended service throughout the city across three separate days last month. The MTA said he pulled wires off the tunnel tracks near the 149th Street-Grand Concourse station, causing the signals in the area to switch from green to red, bringing all train service to a halt.

MTA officials said the problems delayed 755 subway trains across the 1, 2, 3, 4, 5 and 6 lines, which hammered the subway’s on-time performance metrics for October.

“The primary driver of October’s weekday on-time performance decline was a series of atypical vandalism incidents, including three committed by the same individual,” NYC Transit President Demetrius Crichlow said during an MTA board meeting on Wednesday.

Police ended Velez’s alleged crime spree when they arrested him on Oct. 14 and charged him with criminal mischief and trespassing, according to an NYPD spokesperson. Prosecutors accused him of crossing behind a padlocked gate with a “no trespassing sign” to steal the copper wiring, which can be sold at scrapyards for cash.

The delays caused by the thievery added to a difficult year for the MTA. The agency reported 77 “major incidents” — or calamities that delay at least 50 subway trains — last month, the most reported in a single October since 2016. The MTA also wrestled with a spate of subway meltdowns over the summer, primarily caused by infrastructure issues.

Crichlow said the subways are still more reliable this year than they’ve been since the COVID-19 pandemic, with about 85% of weekday trains running on time.

The NYPD alleged that Velez is a serial copper thief. Police said he was arrested in the Bronx in January for robbing a metal manufacturer, stealing copper wires from another Bronx business in February, and trespassing in the 6 train tunnel near Union Square in October.

His most recent arrest highlights security problems that have long vexed MTA officials.

Police have for more than a decade chased a serial metal thief named Prince Hayes throughout the subway system, arresting him multiple times for jacking the MTA’s wires.

Another man was arrested in 2020 after he went onto the subway tracks near the 14th Street station on the A line and placed metal rail tie plates on the tracks, causing a train to derail and crash into support pillars in the tunnel.