In her latest controversial public move, 53-year-old Samantha — who appears to have been in London since late September — was spotted trying to visit Kensington Palace on Saturday.
Meghan, 37, and husband Prince Harry, 34, live in Nottingham Cottage, a 1,300-square-foot, two-bedroom home in the compound of the palace.
Photos taken from the public outing show Samantha, who has multiple sclerosis, being pushed around in a wheelchair while her companion, a man, hands a letter to a palace guard.
Commenting on the contents of the message, Samantha later tweeted, “Everybody would love to know what’s in that letter,” alongside a variety of emojis, including an angel and a kissy face.
Samantha was also seen examining masks of Harry and Meghan’s faces at a merchandise stand during the trip, according to photographs obtained by the Daily Mail.
Samantha — the daughter of Meghan’s father, Thomas Markle, from his first marriage — has been outspoken since Meghan first stepped onto the royal stage. Neither Samantha nor Thomas, 74, attended Meghan’s wedding in May.
In addition to telling the press that she was writing a memoir titled The Diary of Princess Pushy’s Sister, Samantha later took responsibility for arranging Thomas’ staged paparazzi photos in the weeks leading up to the royal wedding — about which Thomas admitted he lied to Harry.
Samantha went on to confess that she had been “cashing in” on Meghan’s fame.
“Let’s face it — we all have to survive. Money makes the world go round, so if you want to call that cashing in, that’s fine, but I think no one in media would refuse a paycheck for talking about the royal and, as a family, we’re not subject to royal protocol,” she told Good Morning Britain in July.
Addressing Meghan and Samantha’s relationship, a source close to the former Suits star previously told PEOPLE that “Meghan has no relationship with her half-siblings, nor has she ever had one.”
“They were out of the house by the time she was born,” added the insider.
Since the wedding, Samantha has amped up her public criticism of Meghan.
“How about you pay tribute to your own father?!” Samantha wrote on Twitter in July, according to Page Six. “Enough is enough. Act like a humanitarian, act like a woman. If our father dies, it’s on you Meg!”
Meanwhile, Thomas has spoken at length about his frustration over the lack of contact he’s had with her, giving multiple explosive interviews.
“It was very wearing on” Meghan, an insider recently told PEOPLE in September, four months after she married Harry. “It’s her private life.”